Unlike previous studies showing IL-9-dependent anti-tumour immune responses in melanoma,26,27 we detected that IL-9 plays a crucial role as a driver of tumour growth in an experimental model of CRC induced by azoxymethane [AOM]/dextran sodium sulphate [DSS] by regulating the IL-6 production by tumour-infiltrating T cells. Here, IL9 is linked to melanoma.