The study hypothesis is that the biomarkers TP53 mutations, MSI, FGA, ATM expression and PARP1/2 expression may be more relevant to CRC biology than HRD because of the rarity of BRCA mutations in CRC and hence, may also be suitable markers for PARPi in this cancer type as is the case for HRD and its surrogates. The gene discussed is ATM; the disease is colorectal carcinoma.