Among the 140 epithelial cells in normal colon tissues, 5.7% of cells expressed ACE2 and 39.3% expressed TMPRSS2; among the 989 epithelial cells in colon cancer tissues, 12.3% expressed ACE2 and 38.5% expressed TMPRSS2 (Fig. 3A–B). Here, ACE2 is linked to malignant colon neoplasm.