Breast Cancer: A Multifactorial Disease with Emerging Precision Medicine Approaches

Breast cancer remains the most prevalent malignancy among women worldwide and continues to be a leading cause of cancer-related mortality. This review highlights the multifactorial etiology of breast cancer, encompassing genetic predispositions, hormonal influences, environmental exposures, and lifestyle choices. Key emphasis is placed on the role of BRCA gene mutations, hormonal replacement therapy, reproductive factors, and obesity in modulating breast cancer risk. The molecular classification of breast cancer into subtypes—Luminal A, Luminal B, HER2-enriched, and Triple-Negative Breast Cancer (TNBC)—has profound implications for prognosis and personalized treatment. The review explores diagnostic modalities such as mammography, ultrasound, biopsy, and immunohistochemistry for precise subtype identification. It also delves into modern therapeutic strategies, including endocrine therapy, chemotherapy, HER2-targeted therapy, and emerging approaches like immunotherapy and precision medicine. Additionally, the impact of treatment-related side effects on patients’ quality of life is examined. Understanding the diverse clinical behavior and biology of breast cancer subtypes is critical to improving outcomes and advancing individualized care.