Apocrine breast cancer. Light micrograph (LM). Apocrine breast cancer is a rare type of invasive ductal breast cancer. Like other types of invasive ductal cancer, apocrine breast cancer begins in the milk duct of the breast before spreading to the tissues around the duct. The cells that make up an apocrine tumor are different than those of typical ductal cancers. Therapy includes surgery (lumpectomy or mastectomy), and may include radiation, endocrine (hormone) therapy, chemotherapy, and therapy that targets the HER2 protein. Magnification: x 150 when printed at 10 centimetres wide. Human tissue