title: ERCC2 2251A>C genetic polymorphism was highly correlated with early relapse in high-risk stage II and stage III colorectal cancer patients: a preliminary study.
abstract: BACKGROUND
  Early relapse in colorectal cancer (CRC) patients is attributed mainly to the higher malignant entity (such as an unfavorable genotype, deeper tumor invasion, lymph node metastasis and advance cancer stage) and poor response to chemotherapy. Several investigations have demonstrated that genetic polymorphisms in drug-targeted genes, metabolizing enzymes, and DNA-repairing enzymes are all strongly correlated with inter-individual differences in the efficacy and toxicity of many treatment regimens. This preliminary study attempts to identify the correlation between genetic polymorphisms and clinicopathological features of CRC, and evaluates the relationship between genetic polymorphisms and chemotherapeutic susceptibility of Taiwanese CRC patients. To our knowledge, this study discusses, for the first time, early cancer relapse and its indication by multiple genes.
  
  
  METHODS
  Six gene polymorphisms functional in drug-metabolism - GSTP1 Ile105Val, ABCB1 Ile1145Ile, MTHFR Ala222Val, TYMS double (2R) or triple (3R) tandem repeat - and DNA-repair genes - ERCC2 Lys751Gln and XRCC1 Arg399Gln - were assessed in 201 CRC patients using a polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) technique and DNA sequencing. Patients were diagnosed as either high-risk stage II (T2 and 3 N0 M0) or III (any T N1 and 2 M0) and were administered adjuvant chemotherapy regimens that included 5-fluorouracil (5FU) and leucovorin (LV). The correlations between genetic polymorphisms and patient clinicopathological features and relapses were investigated.
  
  
  RESULTS
  In this study, the distributions of GSTP1 (P = 0.003), ABCB1 (P = 0.001), TYMS (P < 0.0001), ERCC2 (P < 0.0001) and XRCC1 (P = 0.006) genotypes in the Asian population, with the exception of MTHFR (P = 0.081), differed significantly from their distributions in a Caucasian population. However, the unfavorable genotype ERCC2 2251A>C (P = 0.006), tumor invasion depth (P = 0.025), lymph node metastasis (P = 0.011) and cancer stage (P = 0.008) were significantly correlated with early relapse. Patients carrying the ERCC2 2251AC or2251CC genotypes had a significantly increased risk of early relapse (OR = 3.294, 95% CI, 1.272-8.532).
  
  
  CONCLUSIONS
  We suggest that ERCC2 2251A>C alleles may be genetic predictors of early CRC relapse.
authors.affiliation: Graduate Institute of Medical Genetics, Kaohsiung Medical University, Kaohsiung, Taiwan. miyihu@kmu.edu.tw
authors.forename: Ming-Yii
authors.initials: MY
authors.lastname: Huang
authors.forename: Wei-Yu
authors.initials: WY
authors.lastname: Fang
authors.forename: Su-Chen
authors.initials: SC
authors.lastname: Lee
authors.forename: Tian-Lu
authors.initials: TL
authors.lastname: Cheng
authors.forename: Jaw-Yuan
authors.initials: JY
authors.lastname: Wang
authors.forename: Shiu-Ru
authors.initials: SR
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D044466:Asian People / Q000235:genetics*; D017024:Chemotherapy, Adjuvant; D003082:Colectomy; D015179:Colorectal Neoplasms / Q000208:ethnology / Q000235:genetics* / Q000473:pathology* / Q000628:therapy; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D011446:Prospective Studies; D013624:Taiwan; D051759:Xeroderma Pigmentosum Group D Protein / Q000235:genetics*
chemical_list: D000964:Antimetabolites, Antineoplastic; D051759:Xeroderma Pigmentosum Group D Protein; C497292:ERCC2 protein, human; D005472:Fluorouracil