The STAT3 mutation frequency was not different in the cohorts of T-LGL leukemia with and without SS, totaling 57% (12 of 21 patients) in the cohort of patients with SS and 60% (27 of 45 patients) in the cohort with RD but without SS (p = 1). Here, STAT3 is linked to T-cell large granular lymphocyte leukemia.