title: Molecular markers of response and toxicity to FOLFOX chemotherapy in metastatic colorectal cancer.
abstract: BACKGROUND
  To investigate three genetic alterations (TP53 mutation, Kras mutation and microsatellite instability (MSI)) and three polymorphisms (methylene tetrahydrofolate reductase (MTHFR) C677T, excision repair cross complementing group 1 (ERCC1)-118 and X-ray repair cross complementing group 1 (XRCC1)-399) for their ability to predict response, survival and toxicity to FOLFOX first line chemotherapy in the treatment of metastatic colorectal cancer (mCRC).
  
  
  METHODS
  Tumour tissues from 118 mCRC patients who underwent FOLFOX treatment from three successive phase II trials were evaluated for mutations in TP53 (exons 5-8) and Kras (codons 12 and 13) and for MSI using PCR-based analysis. Genotyping for common single nucleotide polymorphisms in the MTHFR (codon 677), ERCC1 (codon 118) and XRCC1 (codon 399) genes was also carried out using PCR techniques. These genetic markers were correlated with clinical response, survival and toxicity to treatment.
  
  
  RESULTS
  Patients with the T allele of ERCC1-118 showed significantly worse progression-free survival in univariate analysis (HR=2.62; 95% CI=1.14-6.02; P=0.02). None of the genetic alterations or polymorphisms showed significant association with clinical response to FOLFOX. The MTHFR, ERCC1 and XRCC1 polymorphisms showed no associations with overall haematological, gastrointestinal or neurological toxicity to FOLFOX, although MTHFR 677 TT genotype patients showed a significantly higher incidence of grade 3 or 4 diarrhoea (26%) compared with CC or CT genotype patients (6%, P=0.02).
  
  
  CONCLUSIONS
  The ERCC1-118 and MTHFR C677T polymorphisms were associated with progression and severe diarrhoea, respectively, after FOLFOX treatment in mCRC. Although our findings require confirmation in large prospective studies, they reinforce the concept that individual genetic variation may allow personalized selection of chemotherapy to optimize clinical outcomes.
authors: Department of Medical Oncology, Sydney Cancer Centre, Concord Repatriation General Hospital, Sydney, NSW, Australia. weic@med.usyd.edu.au
authors: W
authors: W
authors: Chua
authors: D
authors: D
authors: Goldstein
authors: C K
authors: CK
authors: Lee
authors: H
authors: H
authors: Dhillon
authors: M
authors: M
authors: Michael
authors: P
authors: P
authors: Mitchell
authors: S J
authors: SJ
authors: Clarke
authors: B
authors: B
authors: Iacopetta
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D004268:DNA-Binding Proteins / Q000235:genetics; D004720:Endonucleases / Q000235:genetics; D005260:Female; D005472:Fluorouracil / Q000009:adverse effects / Q000627:therapeutic use; D016158:Genes, p53; D005838:Genotype; D006801:Humans; D002955:Leucovorin / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics; D008875:Middle Aged; D009154:Mutation; D009362:Neoplasm Metastasis; D009944:Organoplatinum Compounds / Q000009:adverse effects / Q000627:therapeutic use; D016016:Proportional Hazards Models; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D000076105:X-ray Repair Cross Complementing Protein 1; D018631:ras Proteins / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; C117307:KRAS protein, human; D009944:Organoplatinum Compounds; D011518:Proto-Oncogene Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2); C071447:ERCC1 protein, human; D004720:Endonucleases; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins; D002955:Leucovorin; D005472:Fluorouracil