TP53 and colorectal cancer: However, in colorectal cancer (CRC), wild-type TP53 was a prerequisite for a PARP inhibitor response because PARPi targeted molecules downstream of p53, especially, GDF15, PLK2, MDM2, TP53INP1, and RRM2B, and attenuated RAD51 foci formation, but not the HRD score [178].