Luminal Breast Cancer

Luminal A breast cancer is a subtype of breast cancer accounting for 40–55% of cases, defined by estrogen receptor (ER) and/or progesterone receptor (PR) positivity, HER2 negativity, and a low Ki-67 proliferation index (<14%), typically presenting as well-differentiated tumors. It is associated with a favorable prognosis and responsiveness to endocrine therapy. Key molecular features include expression of ER/PR, absence of HER2 amplification, and involvement of pathways such as chromatin regulation and acetylation, with HJURP as a related gene. Therapeutic agents like Fulvestrant and Palbociclib are used in treatment. This subtype is linked to tissues including breast and myeloid, and phenotypic traits include increased shRNA abundance and enhanced Salmonella-containing vacuole maturation. Luminal B breast cancer is a hormone receptor-positive (HR+) and HER2-positive breast cancer subtype with a more aggressive phenotype and poorer prognosis compared to luminal A breast cancer. It is characterized by overlapping expression of estrogen and progesterone receptors, increased proliferation, and potential benefit from additional systemic and local therapies. The ERBB2 gene is a key driver, and the condition is linked to pathways such as CREB signaling and ion channel transport. Affected tissues primarily include the breast, and it has associations with familial episodic pain syndrome and mucolipidosis IV.

References: