JAK3 and neoplasm: It has been shown that tumor-derived exosomes can down-regulate CD3ζ and Janus kinase 3 (JAK3) expression in primary activated T-cells, mediate the apoptosis of CD8+ T-cells and the conversion of CD4+ CD25- T-cell into CD4+CD25(hi)FOXP3+regulatory T-cells, (which express interleukin 10, transforming growth factor β1 and cytotoxic T-lymphocyte antigen 4 that effectively mediate suppression) (22) (Figure 2).