TGF-β has been reported to increase glioma-initiating cell self-renewal via STAT3 activation37, and since IL-13 has been shown to induce TGF-β production via IL-13Rα2 in macrophages38, we therefore examined the expression levels of TGF-β in our isogenic glioma cell lines. The gene discussed is TGFB1; the disease is glioma.