The molecular landscape of most T-PLL patients displays recurrence of a complex karyotype, with the overexpression of the proto-oncogene TCL1A/B [1,8], and several activating mutations identified in numerous genes, including those within the IL2RG-JAK1-JAK3-STAT5B pathway [4,9,10,11,12,13]. The gene discussed is TCL1A; the disease is prolymphocytic leukemia.