BRCA1 and cervical squamous intraepithelial neoplasia: HRD, either as a consequence of BRCA1/2 inactivation or mutation in other DNA damage repair genes, is an obvious contributor to CIN, but by itself can only account for up to ∼50% of cases (Cancer Genome Atlas Research Network, 2011; Weaver et al., 2002; Xu et al., 1999).