Additionally, it has recently been demonstrated that human leukocyte antigen G (HLA-G) hinders ADCC by binding to the atypical KIR family receptor KIR2DL4 on NK cells, which may help explain why HER2-positive breast cancer is resistant to trastuzumab treatment (Zheng et al., 2021). This evidence concerns the gene ERBB2 and breast carcinoma.