In diffuse large B-cell lymphoma (DLBCL) patients treated with Rituximab-CHOP (20), breast cancer patients treated with anti-HER2 monoclonal antibody (mAb) and chemotherapy (22), and in colorectal cancer patients treated with anti-EGFR mAb and chemotherapy (24), the tumor-infiltration of NK cells have been reported to positively correlate with clinical responses. The gene discussed is ERBB2; the disease is diffuse large B-cell lymphoma.