PLA2R1 and acute lymphoblastic leukemia: In PB samples, the mean PLA2R1 methylation percentage was 6.5 or 5.1 times higher in pre-B (50.9% ± 20.6%, p < 0.001) and common ALL samples (40.2% ± 25.7%, p < 0.001) in comparison with the control group, respectively (Fig. 1A).