Based on the GEPIA database to test the relative expression of KGs mRNA, it was determined that our proposed KGs (CXCL8, CEMIP, MMP7, CA4, ADH1C, GUCA2A, GUCA2B, ZG16, CLCA4, MS4A12 and CLDN1) may be closely related to the occurrence and development of CRC (Fig. 5). The gene discussed is CA4; the disease is colorectal carcinoma.