DNMT1 and neoplasm: Researches have revealed that DNMT inhibitors could not only increase genes expression related to antigen presentation, promote the presentation of neoantigens and induce the enhancement of major histocompatibility complex (MHC) class I molecules on tumor cells [7], but also elevate the expression of immune co-stimulatory molecules such as CD80, CD86 and CD40, thereby enhance the cytotoxicity of effector T cells on tumors [8].