Interestingly for Q89A, at the antibody concentration (10−2 ng/μl) at which reduced ADCC was observed, this mutant exhibited similar HER2 binding (p = 0.7, Wilcoxon rank-sum test), but inhibited HER2+ cancer cell proliferation (p = 0.1, Wilcoxon rank-sum test) compared to the WT (Figure 4g-i). The gene discussed is ERBB2; the disease is cancer.