Our team is dedicated to finding novel strategies to fight cancer. We are especially focused on strategies that aim to harness the anticancer potential of our immune system. Indeed, in the last ten years, researchers and clinicians have provided the demonstration that in some cancers, therapeutic agents restoring immune responses could successfully treat patients. However, these successes are noted only for a small fraction of cancer patients, underscoring the need to better understand how anticancer immune responses are elicited to develop novel anticancer immunotherapy strategies. We are in that regard interested in a very specific subset of white blood cells, named CD4 T cells. These cells can indeed exert potent anticancer functions when appropriately stimulated. They can for example become IL-9-secreting CD4 T cells (TH9 cells), which have been shown to exert anticancer activities through several ways. Our goal is first to understand the signals that can further enhance CD4 T cell anticancer potential and then use those cells as therapeutic tools. CD4 T cells with a high anticancer potential could be adoptively transferred to patients to favor anticancer immunity and cancer regression.