title: Thymidylate synthetase allelic imbalance in clear cell renal carcinoma.
abstract: OBJECTIVE
  To investigate the allelic status of the thymidylate synthetase (TYMS) gene, located at chromosome band 18p11.32, in renal cell carcinoma (RCC). TYMS is a key target of the 5-fluorouracil (5-FU)-based class of drugs, frequently considered in combination therapies in advanced RCC. TYMS variants, such as the TYMS polymorphic 5'-untranslated region variable number tandem repeat sequence (VNTR), are under investigation to guide 5-FU treatment. Yet, no information is available with regard to changes in TYMS allele frequencies in RCC malignances.
  
  
  METHODS
  Blood and matched tumor samples were collected from 41 histological proven clear cell RCC affected patients (30 males, 11 females.). TYMS VNTR genotype was first determined in blood to identify heterozygotes employing PCR techniques. To evaluate for allelic imbalance, fragment analysis was performed both in blood and matched tumor DNA of the heterozygote patients. Microsatellite analysis, employing the markers D18S59 and D18S476 mapping, respectively, at the TYMS locus (18p11.32) and 1.5 Mb downstream of the TYMS gene sequence (18p11.31), was performed to confirm TYMS allelic imbalance in tumors.
  
  
  RESULTS
  Germ-line TYMS VNTR distribution was: 2R/2R (19.5%), TYMS 2R/3R (36.6%) and TYMS 3R/3R (43.9%). Allelic imbalance for the TYMS tandem repeat region was detected in 26.6% of the heterozygote patients. Microsatellite analysis confirmed the allelic imbalance detected by TYMS VNTR analysis and revealed that the overall frequence of allelic imbalance of chromosome band 18p11.32 was 35%, while the overall allelic imbalance of chromosome band 18p11.31 was 28%.
  
  
  CONCLUSIONS
  By focusing on the TYMS polymorphic variants in renal cancer, we here provide evidence, to our knowledge, for the first time showing loss of 18p11.32 and 18p11.31 in renal cell carcinomas. As allelic imbalances involving TYMS locus may be an important variable affecting 5-FU responsiveness, this study may contribute to explain different responses of advanced RCC in combined chemotherapeutic regimens incorporating fluoropyridines.
authors.affiliation: Research and Innovation S.p.A., Via Svizzera 16, Padua 35127, Italy. microarray@researchinnovation.com
authors.forename: Davide
authors.initials: D
authors.lastname: Colavito
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cartei
authors.forename: Massimo
authors.initials: M
authors.lastname: Dal Bianco
authors.forename: Anna
authors.initials: A
authors.lastname: Stecca
authors.forename: Fable
authors.initials: F
authors.lastname: Zustovich
authors.forename: Maurizio
authors.initials: M
authors.lastname: Dalle Carbonare
authors.forename: Eugenio
authors.initials: E
authors.lastname: Ragazzi
authors.forename: Miriam
authors.initials: M
authors.lastname: Farina
authors.forename: Eva
authors.initials: E
authors.lastname: Colombrino
authors.forename: Alberta
authors.initials: A
authors.lastname: Leon
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D000368:Aged; D022981:Allelic Imbalance / Q000235:genetics*; D002292:Carcinoma, Renal Cell / Q000235:genetics*; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D007680:Kidney Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D013940:Thymidylate Synthase / Q000235:genetics*
chemical_list: D020121:5' Untranslated Regions; D013940:Thymidylate Synthase