The DOI matches its Crossref record; 27 of the 27 references it cites were found in a registry or an index; none of the 23 sources its claims cite is checked for support yet.
High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa
Open accessAbstract
It has been reported that ACE2 is the main host cell receptor of 2019-nCoV and plays a crucial role in the entry of virus into the cell to cause the final infection. To investigate the potential route of 2019-nCov infection on the mucosa of oral cavity, bulk RNA-seq profiles from two public databases including The Cancer Genome Atlas (TCGA) and Functional Annotation of The Mammalian Genome Cap Analysis of Gene Expression (FANTOM5 CAGE) dataset were collected. RNA-seq profiling data of 13 organ types with para-carcinoma normal tissues from TCGA and 14 organ types with normal tissues from FANTOM5 CAGE were analyzed in order to explore and validate the expression of ACE2 on the mucosa of oral cavity. Further, single-cell transcriptomes from an independent data generated in-house were used to identify and confirm the ACE2-expressing cell composition and proportion in oral cavity. The results demonstrated that the ACE2 expressed on the mucosa of oral cavity. Interestingly, this receptor was highly enriched in epithelial cells of tongue. Preliminarily, those findings have explained the basic mechanism that the oral cavity is a potentially high risk for 2019-nCoV infectious susceptibility and provided a piece of evidence for the future prevention strategy in dental clinical practice as well as daily life.
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14 Not checked yet · 8 Own result · 6 Own method · 5 Own interpretation
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The results demonstrated that the ACE2 expressed on the mucosa of oral cavity.”
- Also stated in: § Public bulk RNA-seq dataset analysis · hedged
“According to the mean expression of ACE2, the mucosa of oral cavity could express ACE2, and the results were validated by the data of normal tissues from the FANTOM5 CAGE dataset (Fig. 1b).”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Abstract
boosted- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: Public TCGA para-carcinoma normal tissues and FANTOM5 normal tissues are adequate proxies for normal oral mucosa.
- Rests on an assumption: The FANTOM5 CAGE dataset with only two tongue samples can validate ACE2 expression in the oral cavity.
- Also stated in: § Public bulk RNA-seq dataset analysis · hedged
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Fig. 1a showed that ACE2 could be expressed in various organs, the mean expression of different organs could be found in Table 1.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Results > Public bulk RNA-seq dataset analysis
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: Public TCGA para-carcinoma normal tissues and FANTOM5 normal tissues are adequate proxies for normal oral mucosa.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These findings indicated that oral cavity could be regarded as potentially high risk for 2019-nCov infectious susceptibility.”
- Also stated in: § Abstract · hedged
“Preliminarily, those findings have explained the basic mechanism that the oral cavity is a potentially high risk for 2019-nCoV infectious susceptibility”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Discussion
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: ACE2 RNA expression levels in tissues indicate the presence of functional ACE2 receptor protein and susceptibility to 2019-nCoV infection.
- Also stated in: § Abstract · hedged
None of the sources cited for this claim have been checked yet.
In the paper
“which from our previous project found no significant expression difference among the common epithelial markers in our past study and other previous study22–24.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Discussion
What the sources say
- Not checked yetcites [22] Dionne, K. R., Warnakulasuriya, S., Zain, R. B. & Cheong, S. C. Potentially malignant disorders of the oral cavity: current practice and future directions in the clinic and laboratory. Int. J. Cancer 136, 503–515 (2015). source
- Not checked yetcites [23] Li, J. et al. Associations between proteasomal activator PA28γ and outcome of oral squamous cell carcinoma: evidence from cohort studies and functional analyses. EBioMedicine 2, 851–858 (2015). source
- Not checked yetcites [24] Wang, Z. et al. RACK1, an excellent predictor for poor clinical outcome in oral squamous carcinoma, similar to Ki67. Eur. J. Cancer 45, 490–496 (2009). source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“According to the study of Zhao et al.11, the ACE2 expression in lung is concentrated in a small population of type II alveolar cells (AT2), that may cause the relatively low ACE2 expression of lung in bulk-seq RNA datasets analysis.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Discussion
What the sources say
- Not checked yetcites Zhao et al.11 Zhao, Y. et al. Single-cell RNA expression profiling of ACE2, the putative receptor of Wuhan 2019-nCov. Preprint at https://www.biorxiv.org/content/10.1101/2020.01.26.919985v1 (2020).
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
None of the sources cited for this claim have been checked yet.
In the paper
“Previous studies have investigated the ACE2 mRNA and protein expression in various tissues by bulk samples17,18, however, the distribution of ACE2 through bulk data could not indicate the cell type-specific expression of ACE2.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Discussion
What the sources say
- Not checked yetcites [17] Harmer, D., Gilbert, M., Borman, R. & Clark, K. L. Quantitative mRNA expression profiling of ACE 2, a novel homologue of angiotensin converting enzyme. FEBS Lett. 532, 107–110 (2002). source
- Not checked yetcites [18] Hamming, I. et al. Tissue distribution of ACE2 protein, the functional receptor for SARS coronavirus. A first step in understanding SARS pathogenesis. J. Pathol. 203, 631–637 (2004). source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“These findings indicated that those organs with high ACE2-expressing cells should be considered as potential high risk for 2019-nCoV infection10.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Introduction
What the sources say
- Not checked yetcites [10] Zou, X. et al. The single-cell RNA-seq data analysis on the receptor ACE2 expression reveals the potential risk of different human organs vulnerable to Wuhan 2019-nCoV infection. Front. Med. http://journal.hep.com.cn/fmd/EN/10.1007/s11684-020-0754-0 (2020). source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Zhou et al.4 also proved that 2019-nCoV does not use other coronavirus receptors, aminopeptidase N, and dipeptidyl peptidase 4.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Introduction
What the sources say
- Not checked yetcites Zhou et al.4 Zhou, P. et al. A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature. https://doi.org/10.1038/s41586-020-2012-7 (2020). source
boosted- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“The study of Xu et al.9 found that the RBD domain of the 2019-nCoV S-protein supports strong interaction with human ACE2 molecules.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Introduction
What the sources say
- Not checked yetcites Xu et al.9 Xu, X. et al. Evolution of the novel coronavirus from the ongoing Wuhan outbreak and modeling of its spike protein for risk of human transmission. Sci. China Life Sci. https://doi.org/10.1007/s11427-020-1637-5 (2020). source
boostedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Thus, our results support that in addition to the respiratory droplets and direct contact, fecal–oral transmission might also be the route of transmission of 2019-nCoV.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Discussion
What the sources say
- Not checked yetcites [20] Guan, W.-J. et al. Clinical characteristics of 2019 novel coronavirus infection in China. Preprint at https://www.medrxiv.org/content/10.1101/2020.02.06.20020974v1 (2020).
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: ACE2 RNA expression levels in tissues indicate the presence of functional ACE2 receptor protein and susceptibility to 2019-nCoV infection.
- It may state two separate claims as one. 18
- The quote only partly states this claim. 2
- Probably not a substantial claim. 10
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“and higher in oral tongue than buccal and gingival tissues (95.86% ACE2-positive cells located in oral tongue).”
- Also stated in: § Discussion · boosted
“The results of our single cell RNA-seq profiles validated the ACE2 expression in oral cavity, and the level of ACE2 expression in oral tissues was higher in tongue than buccal or gingival tissues.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Results > Single cell RNA-seq analysis of oral tissues
boostedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The four in-house oral tissue samples are representative of normal oral mucosa and of the oral cavity generally.
- Also stated in: § Discussion · boosted
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“and the ACE2 was highly enriched in epithelial cells, of which 93.38% ACE2-positive cells belong to epithelial cells (Fig. 2f).”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Results > Single cell RNA-seq analysis of oral tissues
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one. The quote only partly states this claim.
- Rests on an assumption: The four in-house oral tissue samples are representative of normal oral mucosa and of the oral cavity generally.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Figure 2e shows that the ACE2-positive cells could be found in oral tissues including epithelial cells (1.19% ACE2-positive cells), T cells (<0.5%), B cells (<0.5%), and fibroblast (<0.5%)”
- Also stated in: § Discussion · plain
“Interestingly, we found that the ACE2 also expressed in lymphocytes within oral mucosa, and similar results were found in various organs of the digestive system and in lungs11,12.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Results > Single cell RNA-seq analysis of oral tissues
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The four in-house oral tissue samples are representative of normal oral mucosa and of the oral cavity generally.
- Also stated in: § Discussion · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“After the data preprocessing (shown in section “Materials and methods”), 22 969 cells were acquired and 7 cell types were identified (Fig. 2a), including epithelial cells”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Results > Single cell RNA-seq analysis of oral tissues
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one. The quote only partly states this claim.
- Rests on an assumption: The four in-house oral tissue samples are representative of normal oral mucosa and of the oral cavity generally.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“When we combined the base of tongue, floor of mouth and oral cavity as other sites, and compared them with oral tongue, we found the obvious tendency that the mean expression of ACE2 was higher in oral tongue (13 tissues) than others (19 tissues) (Fig. 1d), while may due to the limitation of the sample size, the p value was not significant (P = 0.062).”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Results > Public bulk RNA-seq dataset analysis
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The TCGA site annotations for oral cavity samples are accurate.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“According to Fig. 2c, d, we confirmed the ACE2 was expressed in oral tissues (0.52% ACE2-positive cells)”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Results > Single cell RNA-seq analysis of oral tissues
boosted- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The four in-house oral tissue samples are representative of normal oral mucosa and of the oral cavity generally.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The above results indicated that the ACE2 could be expressed on the epithelial cells of the oral mucosa and highly enriched in tongue epithelial cells.”
- Also stated in: § Abstract · plain
“Interestingly, this receptor was highly enriched in epithelial cells of tongue.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Results > Single cell RNA-seq analysis of oral tissues
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The four in-house oral tissue samples are representative of normal oral mucosa and of the oral cavity generally.
- Also stated in: § Abstract · plain
In the paper
“Even though, the result of Zou et al. indicated that the respiratory tract should also be considered as a vulnerable target to 2019-nCoV infection10.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Discussion
What the sources say
- Not checked yetcites [10] Zou, X. et al. The single-cell RNA-seq data analysis on the receptor ACE2 expression reveals the potential risk of different human organs vulnerable to Wuhan 2019-nCoV infection. Front. Med. http://journal.hep.com.cn/fmd/EN/10.1007/s11684-020-0754-0 (2020). source
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“These findings suggest that the ACE2 plays an important role in cellular entry, thus ACE2-expressing cells may act as target cells and are susceptible to 2019-nCoV infection10.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Introduction
What the sources say
- Not checked yetcites [10] Zou, X. et al. The single-cell RNA-seq data analysis on the receptor ACE2 expression reveals the potential risk of different human organs vulnerable to Wuhan 2019-nCoV infection. Front. Med. http://journal.hep.com.cn/fmd/EN/10.1007/s11684-020-0754-0 (2020). source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The ACE2-expressing cells in oral tissues, especially in epithelial cells of tongue, might provide possible routes of entry for the 2019-nCov, which indicate oral cavity might be a potential risk route of 2019-nCov infection.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Discussion
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: ACE2 RNA expression levels in tissues indicate the presence of functional ACE2 receptor protein and susceptibility to 2019-nCoV infection.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“The RNA-seq data were batch effects normalized and log2-transformed for the subsequent analysis.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Materials and methods > Public datasets acquisition and analysis
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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Probably not a substantial claim. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“The “sctransform” wrapper in Seurat was applied to normalize the data and remove confounding sources of variation”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Materials and methods > Single cell RNA-seq data preprocessing and analysis
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Study of Zhou et al.4 indicated that the angiotensin-converting enzyme II (ACE2) is likely the cell receptor of 2019-nCoV, which were also the receptor for SARS-CoV and HCoV-NL637,8.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Introduction
What the sources say
- Not checked yetcites [7] Li, W. et al. Angiotensin-converting enzyme 2 is a functional receptor for the SARS coronavirus. Nature 426, 450–454 (2003). source
- Not checked yetcites [8] Hofmann, H. et al. Human coronavirus NL63 employs the severe acute respiratory syndrome coronavirus receptor for cellular entry. Proc. Natl Acad. Sci. USA 102, 7988–7993 (2005). source
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: fails — The paper’s conclusions may not depend on it.
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Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“The four were taken from three patients with an average age of 50, which were all diagnosed as hyperkeratosis without dysplasia by pathologists, just showing an increase in cell number in the spinous layer and/or in the basal/parabasal cell layers without cellular atypia, and its genetic profiles would be much more closed to normal tissue than malignant tissue22–24.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Materials and methods > Oral tissues of in-house cohort
What the sources say
- Not checked yetcites [22] Dionne, K. R., Warnakulasuriya, S., Zain, R. B. & Cheong, S. C. Potentially malignant disorders of the oral cavity: current practice and future directions in the clinic and laboratory. Int. J. Cancer 136, 503–515 (2015). source
- Not checked yetcites [23] Li, J. et al. Associations between proteasomal activator PA28γ and outcome of oral squamous cell carcinoma: evidence from cohort studies and functional analyses. EBioMedicine 2, 851–858 (2015). source
- Not checked yetcites [24] Wang, Z. et al. RACK1, an excellent predictor for poor clinical outcome in oral squamous carcinoma, similar to Ki67. Eur. J. Cancer 45, 490–496 (2009). source
hedgedn = 3- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Recently developed single-cell RNA-sequencing technology enabled the generation of vast amounts of the transcriptomic data at cellular resolution19.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Discussion
What the sources say
- Not checked yetcites [19] Rostom, R., Svensson, V., Teichmann, S. A. & Kar, G. Computational approaches for interpreting scRNA-seq data. FEBS Lett. 591, 2213–2225 (2017). source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
In the paper
“Study of Zhou et al.4 indicated that the angiotensin-converting enzyme II (ACE2) is likely the cell receptor of 2019-nCoV, which were also the receptor for SARS-CoV and HCoV-NL637,8.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Introduction
What the sources say
- Not checked yetcites Zhou et al.4 Zhou, P. et al. A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature. https://doi.org/10.1038/s41586-020-2012-7 (2020). source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“High ACE2 expression was identified in type II alveolar cells (AT2) of lung10–12, esophagus upper and stratified epithelial cells, absorptive enterocytes from ileum and colon12, cholangiocytes13, myocardial cells, kidney proximal tubule cells, and bladder urothelial cells10.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Introduction
What the sources say
- Not checked yetcites [10] Zou, X. et al. The single-cell RNA-seq data analysis on the receptor ACE2 expression reveals the potential risk of different human organs vulnerable to Wuhan 2019-nCoV infection. Front. Med. http://journal.hep.com.cn/fmd/EN/10.1007/s11684-020-0754-0 (2020). source
- Not checked yetcites [11] Zhao, Y. et al. Single-cell RNA expression profiling of ACE2, the putative receptor of Wuhan 2019-nCov. Preprint at https://www.biorxiv.org/content/10.1101/2020.01.26.919985v1 (2020).
- Not checked yetcites [12] Zhang, H. et al. The digestive system is a potential route of 2019-nCov infection: a bioinformatics analysis based on single-cell transcriptomes. Preprint at https://www.biorxiv.org/content/10.1101/2020.01.30.927806v1 (2020). source
- Not checked yetcites [13] Chai, X. et al. Specific ACE2 expression in cholangiocytes may cause liver damage after 2019-nCoV infection. Preprint at https://www.biorxiv.org/content/10.1101/2020.02.03.931766v1 (2020). source
plain- Asserted: passes — The authors put it forward as true.
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Probably not a substantial claim. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“The uniform manifold approximation and projection (UMAP) was used for dimensionality reduction and clustering the cells, cell types were assigned based on their canonical markers.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Materials and methods > Single cell RNA-seq data preprocessing and analysis
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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Probably not a substantial claim.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Our results are mainly based on public datasets and single cell RNA-sequencing data of in-house oral tissues with minimal diseased lesion”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Discussion
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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Probably not a substantial claim. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“as only two samples of this dataset which owns 60 samples in total located in the tongue, we just downloaded 14 organ types to validate the ACE2 expression in oral cavity with bar plot”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Materials and methods > Public datasets acquisition and analysis
plainn = 2- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The ACE2 expression profile in various organs, tissues, and cell types, provides the bioinformatics evidence for the potential infection routes of 2019-nCov, which might also be associated with presented symptoms.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Discussion
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: ACE2 RNA expression levels in tissues indicate the presence of functional ACE2 receptor protein and susceptibility to 2019-nCoV infection.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“To control quality, we removed cells with <200 genes and 500 UMI counts, and as well as the cells with mitochondrial content higher than 5%. Besides, the genes detected in <3 cells were filtered out.”
§ High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa > Materials and methods > Single cell RNA-seq data preprocessing and analysis
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
The paper relies on this without support.
ACE2 RNA expression levels in tissues indicate the presence of functional ACE2 receptor protein and susceptibility to 2019-nCoV infection.
“The expression and distribution of the ACE2 in human body may indicate the potential infection routes of 2019-nCoV.”
The paper relies on this without support.
The four in-house oral tissue samples are representative of normal oral mucosa and of the oral cavity generally.
“Single cell RNA-seq was utilized for four oral tissues, and the data was analyzed to confirm the above results and assess the cell type-specific expression of ACE2.”
The paper relies on this without support.
Public TCGA para-carcinoma normal tissues and FANTOM5 normal tissues are adequate proxies for normal oral mucosa.
“Bulk RNA-seq data of para-carcinoma normal tissues which were taken as control tissues in the studies were downloaded from The Cancer Genome Atlas (TCGA; https://www.cancer.gov/tcga), and 695 para-carcinoma normal tissues distributed in different organs were obtained for this study”
The paper relies on this without support.
The FANTOM5 CAGE dataset with only two tongue samples can validate ACE2 expression in the oral cavity.
“as only two samples of this dataset which owns 60 samples in total located in the tongue, we just downloaded 14 organ types to validate the ACE2 expression in oral cavity with bar plot”
The paper relies on this without support.
The TCGA site annotations for oral cavity samples are accurate.
“According to the site information provided by the TCGA, among the 32 adjacent normal tissues, 13 tissues located in the oral tongue, 2 tissues located in the base of tongue, 3 tissues located in the floor of mouse, and 14 tissues did not definite the site and were just put into the category of oral cavity.”
The paper relies on this without support.
2019-nCoV infection hardly presents oral symptoms.
“although 2019-ncov infection hardly presented oral symptoms”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“angiotensinconverting enzyme 2 receptor, which is used by SARS-CoV-2 to bind and penetrate into the cell, is widely expressed on the epithelial cells of the mucosa of the oral cavity [7].”
From Self-reported Olfactory and Taste Disorders in Patients With Severe Acute Respiratory Coronavirus 2 Infection: A Cross-sectional Study (2020) · cites this paper as [7]
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
This check didn’t finish.
Citations
Cites
MAFFT Multiple Sequence Alignment Software Version 7: Improvements in Performance and Usability
Katoh, K., & Standley, D. M. (2013) · Molecular Biology and Evolution · doi:10.1093/molbev/mst010 · Cited by 46,209
Clinical characteristics of coronavirus disease 2019 in China
Guan, W.-J., Ni, Z.-Y., Hu, Y., Liang, W.-H., Ou, C.-Q., He, J.-X., Liu, L., Shan, H., Lei, C.-L., Hui, D. S. C., et al. (2020) · New England Journal of Medicine · doi:10.1056/nejmoa2002032 · Cited by 30,246
A novel coronavirus from patients with pneumonia in China, 2019
Zhu, N., Zhang, D., Wang, W., Li, X., Yang, B., Song, J., Zhao, X., Huang, B., Shi, W., Lu, R., et al. (2020) · New England Journal of Medicine · doi:10.1056/nejmoa2001017 · Cited by 28,244
A pneumonia outbreak associated with a new coronavirus of probable bat origin
Zhou, P., Yang, X.-L., Wang, X.-G., Hu, B., Zhang, L., Zhang, W., Si, H.-R., Zhu, Y., Li, B., Huang, C.-L., et al. (2020) · Nature · doi:10.1038/s41586-020-2012-7 · Cited by 21,969
Self-citationWang, D., Hu, B., Hu, C., Zhu, F., Liu, X., Zhang, J., Wang, B., Xiang, H., Cheng, Z., Xiong, Y., et al. (2020) · JAMA · doi:10.1001/jama.2020.1585 · Cited by 20,148
La certeza de lo impredecible: Cultura Educación y Sociedad en tiempos de COVID19
Martínez González, M. (2020) · DSPACE System - Metalibrary (University of the Coast) · Cited by 18,463
Lu, R., Zhao, X., Li, J., Niu, P., Yang, B., Wu, H., Wang, W., Song, H., Huang, B., Zhu, N., et al. (2020) · The Lancet · doi:10.1016/s0140-6736(20)30251-8 · Cited by 11,907
A novel coronavirus outbreak of global health concern
Wang, C., Horby, P. W., Hayden, F. G., & Gao, G. F. (2020) · The Lancet · doi:10.1016/s0140-6736(20)30185-9 · Cited by 7,700
Angiotensin-converting enzyme 2 is a functional receptor for the SARS coronavirus
Li, W., Moore, M. J., Vasilieva, N., Sui, J., Wong, S. K., Berne, M. A., Somasundaran, M., Sullivan, J. L., Luzuriaga, K., Greenough, T. C., et al. (2003) · Nature · doi:10.1038/nature02145 · Cited by 5,923
Hamming, I., Timens, W., Bulthuis, M., Lely, A., Navis, G., & van Goor, H. (2004) · The Journal of Pathology · doi:10.1002/path.1570 · Cited by 5,676
Cited by
Sorted by citations
Virological assessment of hospitalized patients with COVID-2019
Wölfel, R., Corman, V. M., Guggemos, W., Seilmaier, M., Zange, S., Müller, M. A., Niemeyer, D., Jones, T. C., Vollmar, P., Rothe, C., et al. (2020) · Nature · doi:10.1038/s41586-020-2196-x · Cited by 6,661
The trinity of COVID-19: immunity, inflammation and intervention
Tay, M. Z., Poh, C. M., Rénia, L., MacAry, P. A., & Ng, L. F. P. (2020) · Nature Reviews Immunology · doi:10.1038/s41577-020-0311-8 · Cited by 4,360
Extrapulmonary manifestations of COVID-19
Gupta, A., Madhavan, M. V., Sehgal, K., Nair, N., Mahajan, S., Sehrawat, T. S., Bikdeli, B., Ahluwalia, N., Ausiello, J. C., Wan, E. Y., et al. (2020) · Nature Medicine · doi:10.1038/s41591-020-0968-3 · Cited by 3,185
Features, Evaluation and Treatment Coronavirus (COVID-19)
Cascella, M., Rajnik, M., Cuomo, A., Dulebohn, S. C., & Napoli, R. D. (2020) · StatPearls · Cited by 3,351
Lymphopenia predicts disease severity of COVID-19: a descriptive and predictive study
Tan, L., Wang, Q., Zhang, D., Jinya, D., Huang, Q., Wang, Q., Wang, Q., & Miao, H. (2020) · Signal Transduction and Targeted Therapy · doi:10.1038/s41392-020-0148-4 · Cited by 1,722
Metadata
- Authors
- Xu, H., Zhong, L., Deng, J., Peng, J., Dan, H., Zeng, X., Li, T., & Chen, Q.
- Affiliations
- Chinese Academy of Medical Sciences & Peking Union Medical College (CN)
- Corresponding author
- Li, Taiwen
- Venue
- International Journal of Oral Science
- Published
- 2020-02-24
- Volume
- 12
- Issue
- 1
- Pages
- 8-8
- ISSN
- 1674-2818 (ISSN-L)
- 2049-3169
- PMC
- PMC7039956
- OpenAlex
- W3008295344
- Cited by
- 2,838
- References
- 26
- Citations by year
- 2026: 32 · 2025: 59 · 2024: 136 · 2023: 287 · 2022: 469 · 2021: 846 · 2020: 1003
- FWCI
- 85.00
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Locations
- International Journal of Oral Science (publishedVersion, cc-by)
- Europe PMC (PubMed Central) (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Informationszentrum Lebenswissenschaften (ZB MED) (submittedVersion, cc-by)
- PUBLISSO (German National Library of Medicine) (submittedVersion, cc-by)
- Funders
- National Natural Science Foundation of China (111 Project, 81991502, B14038, 81771081, 81520108009, 81991500)
- Ministry of Education, India
- Higher Education Discipline Innovation Project (B14038)
- Topics
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
- Health Sciences › Dentistry › General Dentistry › Dental Research and COVID-19
- Health Sciences › Medicine › Dermatology › Dermatological and COVID-19 studies
- Keywords
- ACE2 receptor, SARS-CoV-2, oral mucosa, host cell receptors, viral entry, infection susceptibility, single-cell transcriptomics, gene expression profiling, dental disease prevention
- MeSH terms
- Betacoronavirus, Angiotensin-Converting Enzyme 2, COVID-19, SARS-CoV-2, Epithelial Cells, Humans, Peptidyl-Dipeptidase A, Mouth Mucosa, Pneumonia, Viral, Tongue, Coronavirus Infections, Gene Expression Profiling, Databases, Genetic
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-09-28, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).
A second model labelled each claim on 2026-09-28 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
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