BRCA1 Expression by Immunohistochemistry and Prognosis in Ovarian Cancer: A Systematic Review and Meta-Analysis

Homologous recombination deficiencies are associated with increased platinum sensitivity and potential response to poly (ADP-ribose) polymerase inhibitors in epithelial ovarian cancer. As an alternative to germline testing or somatic tumor sequencing, BRCA1 deficiency can be detected by immunohistochemistry and might predict homologous recombination deficiencies. This study aimed to assess the association between BRCA1 expression by immunohistochemistry and the prognosis of patients with epithelial ovarian cancer. We conducted a systematic review and meta-analysis following the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement. We searched PubMed, EMBASE, Web of Science, and Scopus databases through July 2019. Reference lists of selected articles were screened for further studies. We conducted qualitative synthesis and meta-analyses of hazard ratios for overall survival and progression-free survival. Of 41 studies of BRCA1 expression using immunohistochemistry, 18 evaluated the association of BRCA1 expression with patient survival (2738 cases). The loss of BRCA1 expression was associated with improved overall survival (hazard ratio = 0.67, 95% confidence interval 0.57–0.77) and progression-free survival (hazard ratio = 0.70, 95% confidence interval 0.58–0.84). Negative BRCA1 expression assessed by immunohistochemistry was associated with a better prognosis in epithelial ovarian cancer.