Mammary ductal carcinoma is the most common type of breast cancer in women. It comes in two forms: invasive ductal carcinoma (IDC), an infiltrating, malignant and abnormal proliferation of neoplastic cells in the breast tissue and ductal carcinoma in situ (DCIS), a noninvasive, possibly malignant neoplasm that is still confined to the lactiferous ducts, where breast cancer most often originates.