luminal A
Pronunciation: LOO-min-al AY
A molecular subtype of breast cancer characterized by hormone receptor positivity, HER2 negativity, and low proliferation markers.
Full Definition
Luminal A is a molecular subtype of breast cancer defined by positive estrogen and/or progesterone receptors, negative HER2 expression, and low proliferation as measured by Ki-67 (typically <14%). This subtype generally has the best prognosis among breast cancer types, with slower growth rates and good response to hormone therapy. Luminal A tumors are typically well-differentiated and less likely to require chemotherapy compared to other subtypes. Treatment usually focuses on endocrine therapy, and these tumors have lower recurrence rates and better overall survival.
Usage
Usage note: Always specify 'A' to distinguish from luminal B subtype.
In Context
- "The tumor was classified as luminal A subtype based on hormone receptor positivity and low Ki-67." — Molecular subtyping report
- "Patients with luminal A breast cancer typically have excellent long-term outcomes with endocrine therapy alone." — Treatment guideline