Antibody-drug conjugates targeting HER2, particularly trastuzumab-deruxtecan, necessitate precise HER2 status characterization in low breast cancers. A study in The American Journal of Surgical Pathology analyzed data from 1,524 estrogen receptor-positive, HER2-negative patients undergoing tumor genomic profiling (2011-2023). HER2 mRNA scores correlated with IHC categories, with median scores rising with higher IHC classifications. Notably, 28 percent of cases displayed discordance between IHC and mRNA scores, suggesting the genomic assay could enhance HER2-low breast cancer identification.
Newsletters
Receive the latest pathologist news, personalities, education, and career development – weekly to your inbox.
