S* pancreatic ductal adenocarcinoma cancer (PDAC) cell line (harboring BRCA2 secondary mutations, c.[6174delT;6182del5]), and the SUM149.B1.S* mammary tumor cell line (with secondary BRCA1 mutations, c.[2288delT; 2293del80]) were insensitive to PARPi after CRISPR mutagenesis was used to reconstitute BRCA function [150, 151]. Here, BRCA2 is linked to breast cancer.