ATM and colorectal carcinoma: The specific objectives include the following: (i) to elucidate the biological significances of the PARPi targets, PARP1/2, in CRC; (ii) to clarify the roles of HRD in predicting PARPi response in CRC; and (iii) to interrogate the potential predictive relevance of PARP1/2 expression, TP53 mutations, ATM expression, MSI status, aneuploidy and fraction genome altered (FGA) in PARP inhibition, and compare these findings to the HRD scores and HRD surrogates.