CA 15-3
{{Expansion depth limit exceeded|Term=CA 15-3 |Short definition=CA 15-3 - A protein found on epithelial cells and is part of a larger protein called MUC 1. CA 15-3 can be found in higher than normal levels in patients with some types of cancer, including breast cancer. |Type=Cancer terms |Specialty=Oncology |Language=English |Source=NCI }} CA 15-3 - A protein found on epithelial cells and is part of a larger protein called MUC 1. CA 15-3 can be found in higher than normal levels in patients with some types of cancer, including breast cancer. Measuring the amount of CA 15-3 in the blood can be useful to check how well the cancer treatment is working or if the cancer has come back. CA 15-3 is a type of tumor marker {{Expansion depth limit exceeded}}