STAT5B and Laron syndrome: Inactivating STAT5B germline mutations (Rajala et al, 2013; Hwa, 2021; Bhattacharya et al, 2022) have been associated with growth hormone insensitivity (Laron syndrome) and immune pathology, whereas activating somatic mutations (Rajala et al, 2013; Kiel et al, 2014; Kontro et al, 2014; Bhattacharya et al, 2022) have been identified in patients with T-cell large granular lymphoblastic leukemia (T-LGLL) (Rajala et al, 2013; Kiel et al, 2014; Kontro et al, 2014; Bhattacharya et al, 2022) and T-cell prolymphocytic leukemia (T-PLL) (Kiel et al, 2014).