Light micrograph showing an invasive ductal carcinoma, the most common type (85%) of invasive breast carcinoma. Breast carcinoma is one of the most common neoplasms in women and is a leading cause of cancer related deaths worldwide. Although the incidence of breast cancer is increasing, the mortality rate from breast cancer is declining. The malignant cells, derived from the lining of the mammary ducts, form irregular ducts or tubules with visible lumina. Mitotic cells are very abundant.