Multidrug Resistance Gene (MDR1) Polymorphism and Response to Nilotinib in Egyptian Patients with Chronic Myeloid Leukemia (CML)

Introduction: Inappropriate expression of the multidrug resistance (MDR1) gene I in chronic phase chronic myeloid leukemia cases (CML-CP) encodes P glycoprotein (Pgp)that may cause resistance to second generation tyrosine kinase inhibitors (TKIs)

Patients and methods: Thirty-one upfront CML-CP patients, planned to receive nilotinib, were included. Detection of MDR1 gene polymorphism C3435T, using PCR Restriction Fragment Length Polymorphisms (PCR-RFLP) was done initially for every patient. We prospectively followed up the patients between February 2012 and February 2014 with PCR for BCR-ABL1 transcripts every 3 months. The molecular response to nilotinib, according to the level of BCR-ABL1 by PCR, was compared to the different MDR1 3435 genotypes.

Results: The majority of the patients carried the MDR1 3435CC genotype of Molecular response was optimal in 56%, 60% and 80% of the patients at month 3, 6 and 12 respectively.There was no statistically significant difference between MDR- C3435T genotypes and the molecular response to treatment with nilotinib.