CEACAM5 and breast cancer: There are several trials using adoptive T cell transfer techniques that are currently enrolling patients with breast cancer: an anti-HER2 bi-armed activated T cells after second line chemotherapy in women with HER2-negative metastatic breast cancer, a chimeric antigen receptor (CAR) T cells targeting cMet (abnormally activated in cancer and correlated with poor prognosis) and last, but not least, a T cell genetically engineered to target carcinoembryonic antigen (CEA) (prominently expressed in breast cancer) [13].