CDKN1A and colorectal carcinoma: Furthermore, chromatin immunoprecipitation analysis demonstrated that EZH2 directly binds to p21 and KLF2 promoter regions and induces H3K27me3 modification, whereas LSD1 directly couples with their promoter regions and enhances H3K4me2 modification in the CRC cells (P<0.05, Figure 4f).