RRM2 and colorectal carcinoma: Luciferase reporter assays showed that overexpression of MYBL2 significantly increased the RRM2 promoter activity, while the truncated promoter (delete site 1), especially the mutated promoter (delete both site 1 and 2) of RRM2 lost the reporter activity induced by the MYBL2 transfection in CRC cells (Figs. 3B, 3C).