Gynecomastia and its potential progression to male breast cancer: Mechanisms, genetic factors, and hormonal interactions.

Gynecomastia is the most common breast condition in men, while male breast cancer remains relatively rare. This review explores the potential relationship between gynecomastia and male breast cancer, with a focus on the roles of hormonal imbalances, genetic factors, and molecular mechanisms in the progression of these conditions. While it remains controversial whether gynecomastia is a precancerous lesion for male breast cancer, this review summarizes the roles of estrogen and androgen receptors, the regulation of aromatase expression, and mutations in key genes such as BRCA1/2. These insights point to possible pathways by which gynecomastia could transition into male breast cancer. Additionally, hormones such as prolactin, insulin-like growth factor-1, and leptin may play significant roles in this progression. We provide an overview of the current understanding and identify key areas for further research, emphasizing the need for large-scale prospective studies to determine the causal relationship between gynecomastia and male breast cancer.