BRCA1 and breast cancer: The etiology of breast cancer is not fully known, but there are several identified factors that increase the risk of the disease, such as genetic burden (presence of BRCA1/2 gene mutations), age (80% of cases occur after the age of 50), history of prolonged exposure to sex hormones (i.e., early menarche, late menopause), years of hormone replacement therapy, lifestyle (poor diet and obesity, insufficient physical activity, frequent alcohol consumption), and history of previous breast diseases [5].