Pathologic complete response to KEYNOTE522 and HER2-directed therapy for synchronous TNBC and HER2+ breast cancer.

ABSTRACT: Simultaneous presentation of two separate primary breast cancers of differing histology at initial diagnosis is an uncommon phenomenon; it is even rarer to find these pathologically distinct populations within the same biopsy. Here we report the case of a patient diagnosed with clearly demarcated, pathologically heterogenous triple negative breast cancer (TNBC) and HER2+ breast cancer that was treated with a hybrid chemoimmunotherapy regimen combining elements of Keynote-522 and a standard HER2-directed neoadjuvant regimen, yielding apathologic complete response by the time of surgery with no notable adverse events. Molecular analysis of the histologically distinct tumor populations confirmed molecular evidence of differential HER2 expression but also suggested clonal relatedness of the tw

SUBMITTER: Mai N 

PROVIDER: S-EPMC11284213 | biostudies-literature | 2024 Jul

REPOSITORIES: biostudies-literature