DNMT1 and neoplasm: More specifically, we demonstrated that in ovarian cancer cell lines with hypermethylation of HLA-A promoter, treatment with demethylating agent 5-aza-2’-deoxycytidine (5-Aza), a DNA methyltransferase (DNMT) inhibitor, can induce the expression of MHC-I protein at the tumour cell surface (Fig. 5c and Supplementary Fig. 6c).