Clinical Significance of FOXP3 Expression in BRCA1/2-Mutant Breast Cancer

ObjectiveTo investigate the potential significance of FOXP3 expression in BRCA1/2-mutant breast cancer. MethodsA total of 48 BRCA mutation carriers (16 with BRCA1 and 32 with BRCA2) and 78 age-matched non-carriers were included in this study. Immunohistochemistry was used to detect the expression of FOXP3 in breast cancer tissues. The FOXP3 RNA expression in 39 BRCA1, 36 BRCA2, and 948 non-carrier breast cancer patients from TCGA-BRCA and the correlation with homologous recombination deficiency scores were evaluated to validate the immunohistochemistry results. ResultsThe FOXP3 positive rate was 43.8% (7/16) in BRCA1 mutation carriers, 59.4% (19/32) in BRCA2 mutation carriers, and 9.0% (7/78) in non-carriers. The FOXP3 positive rates in patients with BRCA1/2 mutant breast cancer were significantly higher than those in non-carriers (P=0.002; P