In a colon cancer study, eight mutations inactivated the normal function of the GalNAcT12 to variable degrees (reduction in enzyme activity: p.R382H, 1%; p.T491M, 2%; p.R373H, 5%; and p.R279W, 7% and p.D303N, 37%), leading to variable phenotypes of colon and breast carcinoma [60]. This evidence concerns the gene GALNT12 and breast carcinoma.