SIRT1 and neoplasm: In the liver metastasis model of colorectal cancer, SIRT-1 attenuates the immunosuppressive ability of MSC and enhances its pro-inflammatory ability by inhibiting the expression of inducible nitric oxide synthase (iNOS) in mesenchymal stem cells by deacetylating p65, thereby increasing the number of CD8+ T cells to enhance local immunity and inhibit tumor development [66].