BRCA1 and breast cancer: Patients carrying a BRCA1 germline mutation overexpressed VDR (BRCA1mut vs. sporadic: IRS 6.00 vs. IRS 3.00%, p < 0.001), RXR (BRCA1mut vs. sporadic: IRS 6.00 vs. IRS 3.00, p = 0.010) and PPARγ (BRCA1mut vs. sporadic: IRS 2.00 vs. IRS 0.00, p < 0.001) when compared to sporadic breast cancer (Fig. 2).