In this study, our data showed a very high autoantibody response rate to BRCA1 (50.0%) but there was a quite low frequency of antibody to BRCA2 (5.9%) in ovarian cancer sera, which were consistent with a previous report that the estimated mutation rates for BRCA 1 and BRCA2 in ovarian cancer were ranged from 22%-65% and 10%-35%, respectively [27]; Some studies further reported that the BRCA2-PARP1 synthetic lethality is probably a hard type of synthetic lethality and the BRCA1-PARP1 synthetic lethality is slightly softer [6]. This evidence concerns the gene BRCA1 and ovarian cancer.