Subsequent experiments proved that TGF-β1-silenced leukemia cell-derived exosomes could promote the proliferation of CD4+ T cells and the secretion of Th1 cytokines, and more effectively stimulate cytotoxic T lymphocyte (CTL) response and NK cytotoxicity, which can inhibit tumor growth and prolong the survival of mice [15]. This evidence concerns the gene TGFB1 and leukemia.