A comprehensive validation of PARP1 and PARP2 expression, TP53 mutation status and MSI status as predictive biomarkers of PARPi response in CRC would require a formal, well-powered clinical trial in which PARP inhibitors are administered to CRC patients—or not—on the basis of the status of the above markers in patients’ tumor. This evidence concerns the gene PARP2 and colorectal carcinoma.