Among the 203 epithelial cells of 266 cells in normal colorectal tissues, 21.7% of cells expressed ACE2 and 70.4% expressed TMPRSS2; among the 272 epithelial cells of 375 cells in colorectal cancer tissues, 13.6% expressed ACE2 and 48.2% expressed TMPRSS2 (Fig. 2B–C). Here, TMPRSS2 is linked to colorectal cancer.