RPN1 and colorectal cancer: According to Bestkeeper software version 1, the most stable and suitable housekeeping genes across our colorectal cancer samples are GAPDH 2 (HGK 1) with standard deviation 0.71 and p = 0.01, PUM1 2 (HGK 2), and RPN1 (HGK 3) are equally good and have the same standard deviations 0.94 and p=0.001.