NA-seq profile data of 13 organs including 695 para-carcinoma normal tissues as control from public TCGA were obtained for our analysis, and Fig. 1a showed that ACE2 could be expressed in various organs, the mean expression of different organs could be found in Table 1. 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).
Fig. 1 Bulk RNA-seq analysis of public datasets. a Violin plot of ACE2 expression in para-carcinoma normal tissues from TCGA, colored by organs. b Bar plot of ACE2 expression in normal tissues from FANTOM5 CAGE dataset, colored by organs. c Bar plot of ACE2 expression of para-carcinoma normal tissues from TCGA in different oral sites, colored by oral sites; d Boxplot of ACE2 in two kinds of oral sites from TCGA, colored by oral sites
Table 1 Sample size and ACE2 expression of para-carcinoma normal tissues in different organs
Sample size ACE2 mean expression Standard deviation of expression
Intestine 51 9.50 1.183
Kidney 129 9.20 2.410
Stomach 35 8.25 3.715
Bile duct 9 7.23 1.163
Liver 50 6.86 1.351
Oral cavity 32 6.23 1.271
Lung 110 5.83 0.710
Thyroid 59 5.65 0.646
Esophagus 11 5.31 1.552
Bladder 19 5.10 1.809
Breast 113 4.61 0.961
Uterus 25 4.37 1.125
Prostate 52 4.35 1.905