To test whether SYCP2 levels are relevant to the DDR drug response in patients, we analyzed 16 breast cancer patients (7 luminal ER/PR positive and 8 triple-negative with no known BRCA mutations, and 1 unknown BRCA status) treated with Sacituzumab Govitecan (IMMU-132), an antibody-conjugated TOP1i for breast cancer treatment33. Here, SYCP2 is linked to breast cancer.