Can HER2 1+ Breast Cancer Be Considered as HER2-Low Tumor? A Comparison of Clinicopathological Features, Quantitative HER2 mRNA Levels, and Prognosis among HER2-Negative Breast Cancer.

ABSTRACT: Background: Human epidermal growth factor receptor 2 (HER2)-low tumor is a new entity defined as HER2 immunohistochemistry (IHC) 1+ or 2+/fluorescence in situ hybridization (FISH)-negative. We aimed to evaluate whether HER2 mRNA levels tested by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) could better define HER2-low tumors. Patients and methods: Consecutive breast cancer patients with hormonal receptor-positive, HER2-negative diseases, and HER2 mRNA results were included. Clinicopathologic features, HER2 mRNA expression level, and prognosis were compared among HER2 0, 1+ and 2+/FISH− groups. Concordance of the HER2 category between qRT-PCR and IHC/FISH was analyzed for each group. Results: 2296 patients were included: 368 (16.0%) HER2 0, 911 (39.7%) 1+, and 1017

SUBMITTER: Shu L 

PROVIDER: S-EPMC9455006 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature