Patients undergoing breast-conserving surgery (BCS) and mastectomy were similar interms of mean age, menopausal status and family history of breast cancer, indicating well-balanced cohorts for comparative analysis.Table 2 (see PDF) presents the tumor characteristics, showing no significant differences between groups with respect to tumor stage,histological subtype (predominantly invasive ductal carcinoma), tumor grade and hormone receptor/HER2 status. The gene discussed is ERBB2; the disease is breast cancer.