EFS on POG 9005/9006 by t(1;19) PCR. (A) EFS of patients for whom all available PCR results were positive versus that of patients for whom all available results were negative plus those with some positive and some negative PCR results (negative + mixed). (B) EFS of patients for whom all available PCR results were negative versus that of patients for whom all available results were positive plus those with some positive and some negative PCR results (positive + mixed). The data were analyzed by the Kaplan-Meier method and the difference compared by the logrank test, the results of which are included in tabular form within each graph.