Comparison of the PP2A and SET protein levels by Western blot between patient samples and normal donors. Phosphorylation on tyrosine-307 of PP2A is also assessed. The K562 cell line was used as a positive control for SET overexpression and hyperphosphorylation of Y-307 of PP2A. N1-N5 indicates normal controls; R, patient sample at relapse; PT, patient sample after treatment; D, patient sample at diagnosis; and C+, K562 cells as positive control.