CTLA4 and colorectal carcinoma: Notably, among genes highly associated with CRC, CTLA4 and the gene encoding DNA polymerase delta (POLD1) had a higher frequency of amplification in low-risk EOCRC, while a higher frequency of POLD1 deletion was observed in high-risk EOCRC (p < 0.05; Fisher’s exact test; Fig. 3G).