In the microarray study of Kager and colleagues, a significant correlation was demonstrated between TYMS, MTHFD1, and RUVBL2 expression and MTXPG accumulation in B-ALL not carrying cytogenetic abnormalities whereas MTHFD2, PPAT, and RUVBL2 expression was associated with MTXPG accumulation within T-ALL. This evidence concerns the gene PPAT and acute lymphoblastic leukemia.