Combined effect of multiple event-predisposing genotypes—DHFR (haplotype *1), thymidylate synthase (TS) 3R3R, and cyclin D1 (CCND1) AA870—on event-free survival in childhood ALL patients. For each group of patients with 0, 1, 2, or 3 of the specified genotypes, the number of patients (and the number of events) are given.