CHEK2 and breast cancer: Actually, we found that 66% of breast cancer samples include a connection between PARP1 and TP53, 70.14% of breast cancer samples include a connection between PARP1 and RRM1, and more than 50% of breast cancer samples include a connection between PARP1 and the other 3 genes RAD50, CHEK2, and BRCA2.