Association of multi-drug resistance gene polymorphisms with pancreatic cancer outcome

Authors

  • Motofumi Tanaka MD, PhD,

    1. Department of Gastrointestinal Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Taro Okazaki MD, PhD,

    1. Department of Gastrointestinal Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Hideo Suzuki MD, PhD,

    1. Department of Gastrointestinal Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • James L. Abbruzzese MD,

    1. Department of Gastrointestinal Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Donghui Li PhD

    Corresponding author
    1. Department of Gastrointestinal Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
    • Department of Gastrointestinal Medical Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Unit 426, Houston, TX 77030
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Abstract

BACKGROUND:

The purpose of this study was to identify single nucleotide polymorphisms (SNPs) of multidrug resistance genes that are associated with clinical outcome in patients with potentially resectable pancreatic adenocarcinoma who were treated with preoperative gemcitabine-based chemoradiotherapy at M. D. Anderson Cancer Center.

METHODS:

We selected 8 SNPs of 7 drug resistance genes, including MDR1 (ABCB1), MRP1-5 (ABCC1-5), and BCRP (ABCG2), reported to be important in mediating drug resistance. Genotype was determined by the Taqman method. The associations of genotype with tumor response to therapy and overall survival (OS) were evaluated using log-rank test, Cox regression, and logistic regression models.

RESULTS:

MRP5 A-2G AA genotype showed significant association with OS (log-rank P = .010). The hazard ratio (95% confidence interval) was 1.65 (1.11-2.45) after adjusting for clinical predictors. The MRP2 G40A GG genotype had a weak association with reduced OS (log-rank P = .097). A combined effect of the two genotypes on OS was observed. Patients with none of the adverse genotypes had a median survival time (MST) of 34.0 months, and those with 1-2 deleterious alleles had a significantly lower MST of 20.7 months (log-rank P = .006). MRP2 G40A GG genotype was also significantly associated with poor histological response to chemoradiotherapy (P = .028).

CONCLUSIONS:

These observations suggest a potential role of polymorphic variants of drug resistance genes in predicting therapeutic efficacy and survival of patients with potentially resectable pancreatic cancer. Cancer 2011. © 2010 American Cancer Society.

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