The KIR-HLA combinations were then described as functional haplotypes and divided in two main categories as inhibitory tel A and stimulatory tel B. Trastuzumab-dependent ADCC activity was monitored with an in vitro assay using a HER2-BC model and patients’ NK cells.We observed a higher frequency of KIR activators in patients who achieved a pCR compared to partial responders. The gene discussed is KIR3DL1; the disease is breast cancer.