Oncotype Dx recurrence score among BRCA1/2 germline mutation carriers with hormone receptors positive breast cancer

Gene expression assays are widely used to predict risk of recurrence in early breast cancer (BC). We report the 21-gene expression assay (Oncotype Dx) recurrence score (RS) distribution of 27 BRCA carriers with estrogen receptor (ER) positive BCs, identified at Hadassah Medical Center, combined with 2 previous studies. Treatment decision and outcomes of the 27 BRCA carriers were compared with an Israeli cohort of 1594 patients published recently. We found Oncotype Dx RS low (<18), intermediate (18-30) and high (>30) among 12 (21.4%), 23 (41.1%) and 21 (37.5%) of 56 BRCA1 carriers compared with 15 (17.2%), 49 (56.3%) and 23 (26.4%) of 87 BRCA2 carriers (p = 0.2). The corresponding distribution in a population of 82,434 women published by Genomic Health was 53.4%, 36.3% and 10.3% for low, intermediate and high RS (p < 0.001 for BRCA1 and BRCA2). Treatment decision regarding chemotherapy according to RS was similar in BRCA1, BRCA2 and the control group. Two of 27 carriers had distant recurrence: a BRCA1 carrier with RS of 18 and a BRCA2 carrier with RS of 22; both have an excellent response to chemotherapy. We found an approximately similar to 3 fold increased rate of high RS among BRCA1 and 2 carriers with ER positive BC compared with the general BC population. These data might indicate that hormone positive BC in BRCA carriers are molecularly unique. The surprisingly good response to chemotherapy in the metastatic setting in 2 patients may suggest that the predictive value of low-intermediate RS in carriers merits further studies.