The ABCB1 and ABCG2 gene expression levels were analyzed using real-time polymerase chain reaction in 61 patients diagnosed with ALL and 99 healthy donors as controls.
Real-time PCR results showed that expression level of MDR1 was significantly higher in AML whereas expression of DHFR, BCRP and Survivin was significantly higher in ALL patients.
Furthermore, the MTHFR 677TT associated with the ABCG2 421GT + TT variant more significantly reduced the risk of adult ALL (OR = 0.32; 95% CI 0.12-0.85).
We found significantly lower expression of the reduced folate carrier (SLC19A1, an MTX uptake transporter) in E2A-PBX1 ALL, significantly higher expression of breast cancer resistance protein (ABCG2, an MTX efflux transporter) in TEL-AML1 ALL, and lower expression of FPGS (which catalyzes formation of MTXPG) in T-lineage ALL, consistent with lower MTXPG accumulation in these ALL subtypes.