STAT5A and neoplasm: While several members of the STAT family, which encompasses STAT1, STAT2, STAT3, STAT4, STAT5A, STAT5B, and STAT6 as a whole, have been linked to tumor initiation and progression (STAT3 and STAT5), others are integral in antitumor defense and the maintenance of an effective and long-term immune response (STAT1 and STAT2) through evolutionarily conserved programs [1].