Germline Mutations Related to Complete Remission After Neoadjuvant Chemotherapy in Patients With Triple-negative Breast Cancer.

[PURPOSE] Triple-negative breast cancer (TNBC) is a frequent phenotype of BRCA-mutant tumors. Tumors with BRCAness may show characteristics of BRCA-mutant tumors and respond to similar treatments. Next-generation sequencing is an efficient and cost-effective method for simultaneously sequencing multiple cancer susceptibility genes, surpassing conventional Sanger testing.

[METHODS] A total of 148 women with TNBC were recruited from December 2015 to November 2018, as part of a sub-analysis based on the PEARLY trial data. Of them, 103 patients received neoadjuvant chemotherapy (NCT). The targeted genes related to hereditary cancers were sequenced using the 65-gene germline next-generation sequencing (gNGS) panel pathogenic and likely pathogenic variants (P&LPs) were determined by Sanger sequencing. We examined the occurrence of pathologic complete remission (ypCR) in patients with P&LPs.

[RESULTS] The patients' median age was 47 years (range, 27-69 years). Twenty (13.7%) of 148 patients had P&LP in six genes, including (n = 2), (n = 9), (n = 5), (n = 1), (n = 1), and (n = 2). Among the 103 patients with NCT, 43 (41.7%) achieved ypCR (P&LPs 9 individuals vs. non-variants; 34 individuals). Among the 103 patients with NCT, 14 (9.3%) had P&LPs. Nine of 14 patients with P&LPs, including (n = 2), (n = 4), (n = 1), (n = 1), and (n = 1), achieved ypCR, showing a trend toward statistical significance ( = 0.066).

[CONCLUSION] Germline P&LP mutations in TNBC patients can be detected by gNGS. This panel test can identify BRCA and BRCAness mutations that may predict ypCR in TNBC.