The multidrug resistance 1 (MDR1) gene plays an important function in carcinogens detoxification and drugs metabolism. Many authors reported that MDR1 gene influences individual susceptibility to cancers. We carried out the present case-control study to investigate the impact of MDR1 gene in the predisposition to acute myeloid leukemia (AML) in a sample of Moroccan population. In addition, we performed a meta-analysis study to discuss our results and to better highlight the influence of MDR1 gene on the susceptibility of AML.
The study included 187 AML patients and 206 controls. Genomic DNA was extracted from white blood cell by salting method. Polymorphisms of G2677 T and C3435 T were genotyped by Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), using Mbo I and Ban I restriction enzymes. Statistical analysis was performed using the software SPSS (version 19.0; SPPS Inc., Chicago, IL, USA) and MedCalcv.11.6.1.0 software.
No statistically significant differences in genotype and allelic distribution were found in G2677 T and C3435 T polymorphisms between AML cases and controls in the Moroccan population. On the other hand, we found that the age of onset of AML in patients with homozygous mutant genotype was statistically lower than in patients with either the heterozygous or wild type genotype for both polymorphisms (P = 0.006; P = 0.03). Meta-analysis showed a significant association of C3435 T, G2677 T polymorphisms on the susceptibility of AML when considering the recessive and the allelic models.
Our findings showed that the G2677 T and C3435 T polymorphisms of the MDR1 gene were associated with the age at onset of AML in our population. In addition, the meta-analysis showed that these polymorphisms could play a role in susceptibility to AML.

The multidrug resistance 1 gene (MDR1) encodes for P-glycoprotein (P-gp), which plays a pathophysiological role in the development of autoimmune diseases, including systemic lupus erythematosus (SLE). Herein, we aimed to investigate the relationship between MDR1 gene polymorphisms and SLE susceptibility in the Chinese Guangxi population. The genotypes of rs1128503 and rs1045642 in MDR1 gene were analyzed using the polymerase chain reaction-restriction fragment length polymorphism method in 283 SLE patients and 247 healthy controls from Guangxi. Direct sequencing method was used to verify the results. Binary logistic regression analyses adjusting for gender and age indicated that subjects carrying the rs1128503 T-allele and TT genotype were at increased risk of SLE when compared to carriers of the C allele and CC genotype, with adjusted ORs of 1.36 (95% CI 1.07-1.74; P = 0.014) and 1.77 (95% CI 1.08-2.88; P = 0.022), respectively. In addition, the risk allele T had a recessive effect (OR 1.49, 95% CI 1.04-2.14, P = 0.029). Subgroup analyses revealed effect modification by age for the presence of the rs1128503 T allele, yielding a significant positive association with SLE in older (≥40 years) subjects (T vs. C allele: OR 1.41, 95% CI 1.01-1.96; P = 0.041; TT vs. CC genotype: OR 1.74, 95% CI 1.07-2.79; P = 0.021). For the first time, we demonstrated that MDR1 rs1128503 polymorphisms were associated with SLE susceptibility in Chinese Guangxi population.