TPMT and acute lymphoblastic leukemia: Adam de Beaumais et al. [6] found that wild-type TPMT/variant ITPA ALL patients treated with the EORTC (European Organization for Research and Treatment of Cancer)-58951 protocol had higher MMPN concentration in erythrocytes in comparison to wild-type TPMT/wild-type ITPA and that a MMPN threshold above 5000 pmol/8 × 108 RBC was associated to an increased risk of hepatotoxicity.