Similarly to sialidase treatment, the cytotoxicity against antibody-opsonized SKBR3 and A431 cells was significantly increased after P3-FAX pre-incubation of the tumor cells and by using the SLC35A1 KO cells (Figure 2g–j), suggesting that tumor cell sialylation limits the efficacy of neutrophil ADCC. The gene discussed is SLC35A1; the disease is neoplasm.