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Updated: Nov 24, 2025
Candidate Gene Testing in Clinical Cohort Studies with Multiplexed Genotyping and Mass Spectrometry
Published on: June 21, 2018
PharmFrag: An Easy and Fast Multiplex Pharmacogenetics Assay to Simultaneously Analyze 9 Genetic Polymorphisms
Régis Bouvet1, Marie-Clémence Verdier2,3,4, Yahya El Baroudi1
1Department of Molecular Genetics and Genomics, Rennes University Hospital, 35000 Rennes, France.
Abstract:
Regarding several cytotoxic agents, it was evidenced that genetic polymorphisms in genes encoding enzymes involved in their metabolism are associated with higher risk of toxicity. Genotyping these genes before treatment is a valuable strategy to prevent side effects and to predict individual response to drug therapy. This pharmacogenetic approach is recommended for chemotherapies such as thiopurines (azathioprine, 6-mercaptopurine, thioguanine), irinotecan, and fluoropyrimidines (capecitabine and 5-fluorouracil). In this study, we aimed at developing and validating a fast, cost-effective, and easily implementable multiplex genotyping method suitable for analyzing a panel of nine variants involved in the pharmacogenetics of widely prescribed anticancer drugs. We designed a multiplex-specific PCR assay where fragments were labeled by two different fluorescent dye markers (HEX/FAM) identifiable by fragment analysis. These two labels were used to discriminate bi-allelic variants, while the size of the fragment allowed the identification of a particular polymorphism location. Variants of interest were TPMT (rs1800462, rs1142345, rs1800460), NUDT15 (rs116855232), DPYD (rs55886062, rs3918290, rs67376798, rs75017182), and UGT1A1 (rs8175347). The assay was repeatable, and genotypes could be determined when DNA sample amounts ranged from 25 to 100 ng. Primers and dye remained stable in a ready-to-use mixture solution after five freeze-thaw cycles. Accuracy was evidenced by the consistency of 187 genotyping results obtained with our multiplex assay and a reference method. The developed method is fast and cost-effective in simultaneously identifying nine variants involved in the pharmacological response of anticancer drugs. This assay can be easily implemented in laboratories for widespread access to pharmacogenetics in clinical practice.
Insights
Genetic testing for cancer drug metabolism genes helps prevent toxicity. A new multiplex genotyping assay efficiently identifies nine key variants, enabling personalized cancer treatment and reducing side effects.
Area of Science:
- Pharmacogenomics
- Molecular Diagnostics
- Oncology
Background:
- Genetic variations in drug-metabolizing enzymes influence anticancer drug efficacy and toxicity.
- Pharmacogenetic testing is crucial for optimizing chemotherapy regimens, including thiopurines, irinotecan, and fluoropyrimidines.
- Current genotyping methods can be time-consuming and costly, limiting widespread clinical application.
Purpose of the Study:
- To develop and validate a rapid, cost-effective, and easily implementable multiplex genotyping assay.
- To simultaneously analyze nine clinically relevant genetic variants in key pharmacogenes (TPMT, NUDT15, DPYD, UGT1A1).
- To facilitate broader clinical adoption of pharmacogenetics for personalized cancer therapy.
Main Methods:
- Design of a multiplex-specific PCR assay utilizing HEX/FAM fluorescent dye markers for fragment analysis.
- Identification of nine single nucleotide polymorphisms (SNPs) across TPMT, NUDT15, DPYD, and UGT1A1 genes.
- Validation of the assay's repeatability, DNA input range (25-100 ng), reagent stability, and accuracy against a reference method.
Main Results:
- The developed multiplex assay successfully identified nine pharmacogenetic variants with high accuracy and repeatability.
- The assay demonstrated stability through multiple freeze-thaw cycles and accommodated a range of DNA concentrations.
- Genotyping results from 187 samples were consistent between the multiplex assay and the reference method, confirming its reliability.
Conclusions:
- A fast, cost-effective multiplex genotyping method for nine anticancer drug pharmacogenetic variants has been developed and validated.
- This assay enables simultaneous analysis, improving efficiency and accessibility for clinical pharmacogenetics.
- Widespread implementation of this assay can enhance personalized cancer treatment strategies and improve patient outcomes by predicting drug response and toxicity.
