FOXL1 and diffuse large B-cell lymphoma: Interleukin 9 receptor (IL9R) accepts IL9, a pleiotropic cytokine, belonging to the group of interleukins, through the signaling transduction proteins HOOK2, FLII, E2F4 in DLBCL ABC and DLBCL GCB, to upregulate TF FOXL1.