The major finding in this report is that CD8+ T cells isolated from RCC patients exhibit defects in proliferation and a propensity to undergo apoptotic cell death as a consequence of reduced expression of JAK3 and MCL-1, the expression of which are regulated in vivo by tumor-induced upregulation of miRNAs miR198 and miR29b, respectively. The gene discussed is JAK3; the disease is renal cell carcinoma.