title: The relative influence of diet and serum concentrations of organochlorine compounds on K-ras mutations in exocrine pancreatic cancer.
abstract: BACKGROUND
  In exocrine pancreatic cancer (EPC) mechanistic relationships may exist among some organochlorine compounds (OCs) and mutations in the K-ras oncogene, as well as among the latter and dietary factors.
  
  
  OBJECTIVE
  To analyze (1) the relationship between food intake and serum concentrations of OCs in EPC patients and (2) the relative influence of food and OCs on the frequency of K-ras mutations in EPC.
  
  
  METHODS
  Incident cases of EPC were prospectively identified, and interviewed face-to-face during hospital admission (N=135 patients with data on OCs and diet, and N=97 with additional information on K-ras status). OCs were measured by high-resolution gas chromatography with electron-capture detection.
  
  
  RESULTS
  Consumption of milk and other dairy products was positively associated with concentrations of p,p'-DDT, PCB 138 and PCB 153 (log-transformed betas=0.652, 0.588 and 0.317, respectively; all p<0.05). When adjusted by OCs, dairy products were no longer associated with K-ras. By contrast, after adjusting by consumption of dairy products, patients with the highest concentrations of p,p'-DDT and some PCBs remained more likely to have a K-ras-mutated EPC than patients with lower concentrations (OR for upper tertile of PCB 138=5.5, 95% CI: 1.3-23.4).
  
  
  CONCLUSIONS
  Dairy products were a source of OCs. The association between dairy products and K-ras mutations was not independent of OCs. By contrast, the association between OCs and K-ras was not confounded by dairy products. OCs may be more likely to contribute to the occurrence of K-ras mutations than nutrients contained in dairy products.
authors.affiliation: Institut Municipal d'Investigació Mèdica, Barcelona, Catalonia, Spain.
authors.forename: Magda
authors.initials: M
authors.lastname: Gasull
authors.forename: Miquel
authors.initials: M
authors.lastname: Porta
authors.forename: José
authors.initials: J
authors.lastname: Pumarega
authors.forename: Jesús
authors.initials: J
authors.lastname: Vioque
authors.forename: Magda
authors.initials: M
authors.lastname: Bosch de Basea
authors.forename: Elisa
authors.initials: E
authors.lastname: Puigdomènech
authors.forename: Eva
authors.initials: E
authors.lastname: Morales
authors.forename: Joan O
authors.initials: JO
authors.lastname: Grimalt
authors.forename: Núria
authors.initials: N
authors.lastname: Malats
mesh_terms: D000368:Aged; D000818:Animals; D002417:Cattle; D002849:Chromatography, Gas; D004032:Diet; D004785:Environmental Pollutants / Q000097:blood* / Q000737:chemistry; D005260:Female; D005504:Food Analysis; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000097:blood* / Q000737:chemistry; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D008892:Milk / Q000737:chemistry; D009154:Mutation; D010190:Pancreatic Neoplasms / Q000097:blood* / Q000453:epidemiology / Q000235:genetics; D018631:ras Proteins / Q000235:genetics*
chemical_list: D004785:Environmental Pollutants; D006843:Hydrocarbons, Chlorinated; D018631:ras Proteins