Among the subset of patients with CML in the chronic phase undergoing TKI initiation (n = 51), ‘intermediate’ TGF-β1 gene expression was 4/22 (18%) for patients with favorable and 9/29 (31%) with unfavorable clinical outcomes. The gene discussed is TGFB1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.