There have revealed multiple mutation hot-spots within SH2 and C-terminal domains in STAT5B, among which N642H has been discovered in various hematological malignancies of T cell origin including T-cell acute lymphoblastic leukemia(T-ALL), T-cell prolymphocytic leukemia(T-PLL), and MEITL [28]. The gene discussed is STAT5B; the disease is acute lymphoblastic leukemia.