Strikingly, however, mice that received Dbp shRNA-engineered T cells that decreased IL-9 (Fig. 6a) were less effective at eliminating tumor than normal Th9 cells (Fig. 6b), whereas mice that received E2f8 shRNA-engineered T cells that increased IL-9 (Fig. 6a) showed significantly slower tumor growth, when compared to mice that received T cells treated with the control shRNA (Fig. 6b). The gene discussed is E2F8; the disease is neoplasm.