title: Glutathione S-transferase P1 polymorphism (Ile105Val) predicts cumulative neuropathy in patients receiving oxaliplatin-based chemotherapy.
abstract: OBJECTIVE
  Glutathione S-transferases (GST) are xenobiotic metabolizing enzymes involved in the detoxification of a variety of chemotherapeutic drugs, including platinum derivatives. Genetic polymorphisms of GSTs have been associated with enzyme activity variations. Thus, a study was done to investigate the relationship between GST polymorphisms and oxaliplatin-related cumulative neuropathy in gastrointestinal cancer patients treated with oxaliplatin-based chemotherapy.
  
  
  METHODS
  Ninety patients were included. Clinical neurologic evaluation was done at baseline and before each cycle of treatment. We determined genetic variants for GSTP1 exon 5 (Ile105Val), GSTP1 exon 6 (Ala114Val), GSTM1 (homozygous deletion), and GSTT1 (homozygous deletion). We conducted analyses in a subgroup of 64 patients receiving a minimal cumulative dose of 500 mg/m2 of oxaliplatin to examine whether the GST polymorphisms are associated with oxaliplatin-related cumulative neuropathy.
  
  
  RESULTS
  Among patients receiving a minimal cumulative dose of 500 mg/m2 of oxaliplatin, 15 patients showed clinically evident oxaliplatin-related cumulative neuropathy scored grade 3 according to an oxaliplatin-specific scale. The oxaliplatin-related cumulative neuropathy scored grade 3 was significantly more frequent in patients homozygous for the GSTP1 105Ile allele than in patients homozygous or heterozygous for the GSTP1 105Val allele (odds ratio, 5.75; 95% confidence interval, 1.08-30.74; P = 0.02). No association was found with respect to any of the GSTM1, GSTT1, or GSTP1 exon 6 genotypes.
  
  
  CONCLUSIONS
  The results of the current study suggest that the 105Val allele variant of the GSTP1 gene at exon 5 confers a significantly decreased risk of developing severe oxaliplatin-related cumulative neuropathy.
authors.affiliation: Department of Gastroenterology, Assistance Publique-Hôpitaux de Paris, European Georges Pompidou Hospital, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Lecomte
authors.forename: Bruno
authors.initials: B
authors.lastname: Landi
authors.forename: Philippe
authors.initials: P
authors.lastname: Beaune
authors.forename: Pierre
authors.initials: P
authors.lastname: Laurent-Puig
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Loriot
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000188:drug therapy; D020022:Genetic Predisposition to Disease; D051549:Glutathione S-Transferase pi / Q000235:genetics* / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000139:chemically induced* / Q000235:genetics; D009944:Organoplatinum Compounds / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D000077150:Oxaliplatin; D011110:Polymorphism, Genetic; D012189:Retrospective Studies
chemical_list: D000970:Antineoplastic Agents; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; C413545:glutathione S-transferase T1; C496556:GSTP1 protein, human