BRCA2 and ductal breast carcinoma in situ: AAbs to BRCA1 and BRCA2 protein were identified by ELISA in the sera of 8/94 (8.5%) and 32/94 (34%) invasive breast carcinoma patients, respectively, and 1/40 (2.5%) and 9/40 (22.5%) ductal carcinoma in situ patients, respectively [23].