MDR1 polymorphisms have an impact on the prognosis of Chinese diffuse large B cell lymphoma patients

Effect of ABC transporter expression and mutational status on survival rates of cancer patients

ATP-binding cassette (ABC) transporters mediate multidrug resistance in cancer. In contrast to DNA single nucleotide polymorphisms in normal tissues, the role of mutations in tumors is unknown. Furthermore, the significance of their expression for prediction of chemoresistance and survival prognosis is still under debate. We investigated 18 tumors by RNA-sequencing. The mutation rate varied from 27,507 to 300885. In ABCB1, three hotspots with novel mutations were in transmembrane domains 3, 8, and 9. We also mined the cBioPortal database with 11,814 patients from 23 different tumor entities. We performed Kaplan-Meier survival analyses to investigate the effect of ABC transporter expression on survival rates of cancer patients. Novel mutations were also found in ABCA2, ABCA3, ABCB2, ABCB5, ABCC1-6, and ABCG2. Mining the cBioPortal database with 11,814 patients from 23 different tumor entities validated our results. Missense and in-frame mutations led to altered binding of anticancer drugs in molecular docking approaches. The ABCB1 nonsense mutation Q856* led to a truncated P-glycoprotein, which may sensitize tumors to anticancer drugs. The search for ABC transporter nonsense mutations represents a novel approach for precision medicine.. Low ABCB1 mRNA expression correlated with significantly longer survival in ovarian or kidney cancer and thymoma. In cancers of breast, kidney or lung, ABC transporter expression correlated with different tumor stages and human populations as further parameters to refine strategies for more individualized chemotherapy.

Clinical relevance of multi-drug resistance gene C3435T polymorphism in diffuse large B-cell lymphoma in Xinjiang

To explore the relationship between C3435T polymorphism of multi-drug resistance gene (MDR1) gene and susceptibility, clinicopathological characteristics, curative effect and hematological toxicity of diffuse large B-cell lymphoma (DLBCL) in XinJiang.The peripheral venous blood samples of 54 patients with DLBCL and 60 healthy controls were collected. The alleles and genotypes of MDR1 gene C3435T were detected by DNA direct extraction with PCR technique, and the frequency of C3435T allele and genotypes were detected by the chi-square test. The relationship between the allele and genotype distribution of C3435T locus and the susceptibility, clinicopathological characteristics, curative effect and hematological toxicity of DLBCL were analyzed.1 the frequency of CT heterozygote and CC homozygote mutation was significantly higher in the case group (46.3% in CT genotype and 42.6% in CC genotype) compared to the control group (P < 0.05). The frequency of CC genotype mutation in the case group was 42.6%, which was significantly higher than that in the control group (P < 0.05, OR 3.209, 95% CI: 1.288-7.997). 2 the genotypes of C3435T locus of MDR1 gene were distributed in age, sex, nationality, pathological characteristics, clinical-stage, IPI index, B symptoms, infection with EB virus, clinicopathological characteristics and clinical efficacy of hepatitis B in patients with DLBCL. There was no significant difference in myelosuppression (P > 0.05).The homozygous mutation genotype of CC is the risk genotype of DLBCL. The alleles and genotypes are not associated with the clinicopathological characteristics, efficacy and myelosuppression toxicity of DLBCL.

MDR1 polymorphisms affect the outcome of Chinese multiple myeloma patients

OBJECTIVE

To illustrate the association of MDR1 (Multidrug Resistance 1) polymorphisms at loci 1236, 2677, 3435 and the prognosis of multiple myeloma (MM) in Jiangsu population.

METHODS

A total of 129 MM patients were recruited from Jiangsu Province, China. The DNA was extracted from white blood cells (WBC) of peripheral blood and was amplified by polymerase chain reaction-allele specific primers (PCR-ASP). MDR1 polymorphisms at 3 loci were analyzed by electrophoresis followed by photograph or DNA direct sequencing. The association between the MDR1 and clinical outcomes were calculated by Graphpad and SPSS.

RESULTS

MDR1 alleles at locus C1236T with T had significant lower calcium level in MM patients compared with C. The genotype CT had a significantly prolonged progress free survival (PFS) compared genotype CC at locus C1236T (median time: 48 months vs. 28 months, respectively; p=0.0062; HR=0.21; 95%CI0.061-0.715) while patients carrying T allele (CT and TT) at locus C3435T had a longer PFS than patients without T allele (CC) (median time: 60 months vs. 29 months, respectively; p=0.038; HR=0.508; 95%CI 0.264-0.978). And a borderline significance was found in haplotype at loci 2677-3435 and PFS. No significant findings were revealed between OS and MDR1 polymorphisms.

CONCLUSION

MDR1 polymorphisms could affect the prognosis of multiple myeloma whereas more samples and a longer follow-up are also needed.