Definitive genetic evidence is provided by studies in specific cancer models: re‐expression of an O‐GlcNAcylation‐defective SNAP‐29 mutant, but not wild‐type SNAP‐29, rescues the fusion block induced by arsenic in cervical cancer HeLa cells or by the cytotoxic compound SM15 in treated cancer cells.89, 91. The gene discussed is SNAP29; the disease is cancer.