C1GALT1C1 and cancer: During carcinogenesis, C1GALT1C1 expression could be downregulated due to genetic mutations [105] or, more interestingly, to an epigenetic modification: hypermethylation of the promoter leads to the silencing of C1GALT1C1 and to the accumulation of the cancer-associated Tn and STn antigens [106,107].