CD4 and lung cancer: Thus, a reduction in IFNγ expression of CD4+ T cells cocultured with lung cancer cell is correlated with the hypermethylation of IFNγ promoter.9 These findings suggest that interaction between lung cancer cells and CD4+ T cells induces DNMT expression and hypermethylation of IFNγ promoter in CD4+ T cells, which silence IFNγ gene expression.