Researchers have shown that a synthetic IL-9 receptor allows anti-cancer T cells to do their job without the need for chemo or radiation. T cells modified with the synthetic IL-9 receptor were potent against tumours in mice, as published in Nature. This group of researchers were interested in testing modified versions of the synthetic receptor that transmit other cytokine signals from the common gamma chain family: IL-4, -7, -9 and -21. Of the synthetic common gamma chain signals, the IL-9 signal was worth studying and unlike other cytokines, IL-9 signalling is not generally active in naturally ocurring T cells. The synthetic IL-9 signal gave the T cells a unique blend of stem cell and killer cell qualities that made them more robust in fighting tumours. In particular, the researchers targeted two types of difficult-to-treat cancer models in mice: pancreatic cancer and melanoma. They used T cells targeted to the cancer cells via the natural T cell receptor or a chimeric antigen receptor (CAR). In all cases, T cells engineered with synthetic IL-9 receptor signalling were superior and helped cure some tumours in mice when they could not do otherwise.