And since trastuzumab, and not chemotherapy alone, is the standard of care for the HER2-positive sub-class of breast cancer, there is no need to test for these lymphocytes in HER2-positive patients in order to predict outcome, say researchers from Mayo Clinic in Florida. These findings, presented at the 2014 San Antonio Breast Cancer Symposium, don’t mean that immune function in this class of cancer isn’t important — just that it is likely more complicated than measuring the number of these lymphocytes, says the study’s lead author, Edith A. Perez, M.D., deputy director at large, Mayo Clinic Cancer Center, and director of the Breast Cancer Translational Genomics Program at Mayo Clinic in Florida. “Researchers are really interested in the different components of the immune system as a predictor of the natural history of breast cancer and benefit from different therapies, but it may be that when trastuzumab is used, it is the function of the immune system and not the number of lymphocytes that is important,” Dr. …