Kaplan-Meier analyses of DFS in S-form versus L-form PML-RARα mRNA type cases. (A) All cases; (B) ATRA induction treatment cases; (C) chemotherapy induction treatment cases. The legend denominator indicates the number of protocol cases at risk in successive 6-month intervals up to 4 years of follow-up beginning from the time of the clinical diagnosis of CR. The legend numerator indicates the number of cases at risk that experienced adverse events leading to an off-protocol status (relapse or death).