Proteomics based selection achieves complete response to HER2 therapy in HER2 IHC 0 breast cancer.

ABSTRACT: Recent trials have shown the efficacy of trastuzumab deruxtecan (T-DXd) in HER2-negative patients, but there is not yet a way to identify which patients will best respond, especially with the inability of current HER2 IHC and FISH assays to accurately determine HER2 expression in the unamplified setting. Here, we present a heavily pre-treated patient with triple-negative breast cancer (HER2 IHC 0 who had a complete response to T-DXd. In this case, we used a CLIA-certified reverse-phase protein array-based proteomic assay (RPPA) to determine that the patient had moderate HER2 protein expression (HER2^Total 2+, 42%) and activation (HER2^Y1248 1+, 23%). Using these results, we determined that the patient may benefit from T-Dxd despite being traditionally qualified as HER2

SUBMITTER: Johnston LE 

PROVIDER: S-EPMC11401868 | biostudies-literature | 2024 Sep

REPOSITORIES: biostudies-literature