molecular subtyping
Classification of breast cancers based on gene expression patterns that define biologically distinct tumor types with different treatment implications.
Full Definition
Molecular subtyping is a classification system that categorizes breast cancers into distinct subtypes based on their molecular characteristics, particularly gene expression profiles. The primary subtypes include luminal A, luminal B, HER2-enriched, and basal-like tumors. This classification is typically approximated in clinical practice using immunohistochemical markers for estrogen receptor, progesterone receptor, HER2, and Ki-67. Molecular subtyping provides valuable information about tumor biology, prognosis, and treatment response patterns. It helps guide therapeutic decisions by identifying tumors likely to respond to specific targeted therapies and predicting sensitivity to chemotherapy and endocrine therapy. Advanced molecular assays like PAM50 can provide more precise subtype classification than immunohistochemistry alone.
Usage
Usage note: Distinguish from simple receptor status testing; molecular subtyping encompasses broader biological characterization.
In Context
- "Molecular subtyping revealed a luminal B tumor requiring both endocrine and chemotherapy." — Treatment planning document
- "The PAM50 assay provided definitive molecular subtyping for this borderline case." — Laboratory report