Our finding showed that YWHAZ + B2M is the optimal panel of reference genes in the normal human colonic epithelial cell lines (NCM460) and some CRC cell lines (HCT116, SW620, LOVO, RKO, SW480, and HT29), while it is PPIA + GUSB in DLD-1 cell lines. The gene discussed is GUSB; the disease is colorectal carcinoma.