CD4 and breast carcinoma: Therefore, we hypothesized that in patients with metastatic HER2 + breast cancer treated with trastuzumab, the elevated levels of miR-19a-3p, associated with a better prognosis, may result from passive release from apoptotic or dead tumor cells killed by NK cell-mediated ADCC [45] and the effective activation of CD4 + Th1 cells.