Human mammaglobin is a member of the uteroglobin proteins family that has recently been tested as a specific marker for breast cancer. While low levels may be seen in normal breast tissue, expression is increased dramatically in breast cancer and is correlated with higher grade. Detection in blood and body fluids is also correlated with cancer metastasis, and its levels with prognosis. This promises to be a useful screen for early detection of breast cancer, especially in high risk individuals. Mammoglobin has also been used for immunotherapeutic targeting of breast cancer cells. However, there are some controversies regarding its diagnostic efficacy and prognostic value, which warrant further study.