EFS of patients with T-lineage ALL according to the apparent maturational stage of bone marrow leukemic blasts. EFS for (A) mature TL, (B) CD2⁺ immature TL, (C) CD2⁻immature TL, and (D) pro-TL patients treated on the 1800 series of CCG protocols are shown. EFS values at designated points in follow-up are given in the text.