Breast cancer is a major global health issue, with high diagnosis rates worldwide, especially in less developed areas, leading to significant mortality rates. This review focuses on the molecular characteristics of breast cancer, emphasizing the role of human mammaglobin-A (hMAM-A) as a diagnostic and prognostic marker. hMAM-A, a dimeric protein from the secretoglobin family, is produced exclusively by breast tissue and shows elevated levels in breast cancer cases, making it a highly accurate marker for disease detection. The review also examines various factors influencing breast cancer, such as age, tobacco use, menopausal status, and hormone replacement therapy (HRT). Younger age at diagnosis is associated with poorer outcomes, highlighting the importance of early detection. Tobacco smoke increases mortality rates in breast cancer patients. Menopausal status affects molecular subtypes and risk factors, impacting treatment and prognosis. HRT has a complex relationship with breast cancer risk. The review concludes by discussing the need for novel biomarkers, including hMAM-A, to improve breast cancer diagnosis and management.