FOXP1, part of the Foxp subgroup within the forkhead TF family, is pivotal in immune responses, organ development and cancer pathogenesis 125-127, while also maintaining the quiescence and homeostasis of naïve T cells, partly by antagonizing FOXO1 interaction with shared forkhead-binding sites within the IL-7Rα enhancer, thus repressing IL-7Rα expression and MEK-Erk signaling. Here, IL7R is linked to cancer.