Consequently, it comes as no surprise that cytokines, the so-called messengers of the immune system, have received increasing research attention during the last decade, already yielding remarkable results in the clinic.1 Interleukin 27 (IL-27), a heterodimeric cytokine belonging to the IL-12 family, has been the subject of a number of recent studies investigating its involvement in cancer development and progression, generating truly significant but rather pleotropic results for distinct malignancies. This evidence concerns the gene IL27 and cancer.