Overall survival by TCR status. (A) Overall survival was not different in patients with IM (solid line) compared with TCR⁺ T-ALL (thin dotted line). Bold dotted line indicates pre-αβ ALL. (B) Pre-αβ ALL (solid line) vs all others (dotted line). Survival was significantly better in the pre-αβ subset compared with the 62 other patients with either IM or TCR⁺ ALL (59% versus 32% at 4 years; P = .02 by the log-rank test).