title: Simultaneous detection of variable number tandem repeats, single nucleotide polymorphisms, and allelic imbalance in the thymidylate synthase gene enhancer region using denaturing high-performance liquid chromatography.
abstract: Polymorphisms in the thymidylate synthase enhancer region (TSER) have been reported to be associated with alterations in thymidylate synthase (TS) mRNA protein levels. The TSER is characterized by the presence of variable double (2R) and triple (3R) number tandem repeats (VNTRs). In addition to VNTRs, single nucleotide polymorphisms (SNPs) and allelic imbalance (AI), including loss of heterozygosity (LOH), have recently been associated with response to 5-fluorouracil (5-FU)-based chemotherapy. The aim of the current study was to develop a specific denaturing high-performance liquid chromatography (DHPLC) method for the rapid detection of these variations in the TSER in clinical samples. DHPLC analysis was validated in parallel with agarose gel electrophoresis (AGE), enzyme digestion, and quantitative reverse transcription-polymerase chain reaction (Q-RT-PCR). The optimized DHPLC method resolved 100% of the known TSER variations, differentiated between homozygous and heterozygous genotypes, and allowed the qualitative and quantitative detection of AI, including LOH, in tumor samples. This DHPLC method was developed to permit the rapid, sensitive, and accurate identification of the TSER genotype (VNTRs, SNPs, and AI) in clinical protocols where response to flouropyrimidines may be correlated with TSER polymorphisms.
authors.affiliation: Department of Clinical Pharmacology, University of Alabama at Birmingham, Comprehensive Cancer Center, Birmingham, AL 35294, USA.
authors.forename: Hany
authors.initials: H
authors.lastname: Ezzeldin
authors.forename: Cornelia
authors.initials: C
authors.lastname: Hoffmayer
authors.forename: Richie
authors.initials: R
authors.lastname: Soong
authors.forename: Martin R
authors.initials: MR
authors.lastname: Johnson
authors.forename: Adam
authors.initials: A
authors.lastname: Lee
authors.forename: Marty
authors.initials: M
authors.lastname: Heslin
authors.forename: Robert
authors.initials: R
authors.lastname: Diasio
mesh_terms: D022981:Allelic Imbalance / Q000235:genetics*; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000737:chemistry / Q000235:genetics; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D005787:Gene Frequency; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D009691:Nucleic Acid Denaturation; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012680:Sensitivity and Specificity; D020080:Tandem Repeat Sequences / Q000235:genetics*; D013940:Thymidylate Synthase / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D004247:DNA; D013940:Thymidylate Synthase; D015252:Deoxyribonucleases, Type II Site-Specific; C024403:GGCC-specific type II deoxyribonucleases