ITPR1 and neoplasm: Furthermore, inosine was shown to mediate these anti-tumor immune effects only via T cells, as direct administration of inosine to MC38 tumor cells did not alter tumor viability.19 In conjunction with anti-CLA-4 therapy, inosine and inosine-producing bacterial species were able to, via A2AR-mediated effects on T cells, reduce tumor size significantly more than anti-CLA-4 therapy alone.