Endoscopy 2005; 37 - A17
DOI: 10.1055/s-2005-922879

Gene-diet interactions in the aetiology of colorectal cancer: results from a population-based case-control study in north-east Scotland

L Sharp 1, LF Masson 2, J Little 3, NT Brockton 2, 4, SC Cotton 2, NE Haites 4, J Cassidy 4
  • 1National Cancer Registry Ireland, Elm Court, Boreenmanna Road, Cork, Ireland
  • 2Dept. Public Health, University of Aberdeen, Scotland
  • 3Dept. Epidemiology & Community Medicine, University of Ottawa, Canada
  • 4Dept. Medicine & Therapeutics, University of Aberdeen, Scotland

Aims: Folate, green vegetables and meat intake have all been linked with colorectal cancer (CRC) risk; variation in genes encoding enzymes involved in metabolising these factors might modify diet-CRC associations. We undertook a case-control study to investigate diet, MTHFR, GSTM1, GSTT1 and CYP1A1 polymorphisms and CRC.

Methods: Cases were Grampian residents with histological confirmed CRC diagnosed September 1998-February 2000. Controls were selected from Grampian GP registers. Subjects completed a dietary questionnaire. DNA was extracted from mouthwash samples. MTHFR and CYP1A1 polymorphisms were detected by PCR with digestion with HinfI(C677T), MboII(A1298C), MspI(m1), BsrD1(m2) and BsaI(m4) respectively. GSTM1 and GSTT1 deletions were detected by PCR. Adjusted odds ratios were calculated by logistic regression.

Results: 264 cases (62% of those eligible) and 408 controls (61%) participated. CRC risk was slightly decreased in those carrying MTHFR variant alleles. There were significant interactions between MTHFR genotype and folate intake. Individuals possessing the CYP1A1 m4 variant had reduced risk. CYP1A1 m1 and m2 polymorphisms significantly modified associations between green leafy vegetable intake and CRC. CYP1A1 polymorphisms interacted with meat intake. GSTM1 and GSTT1 were unrelated to CRC.

Conclusions: Associations between dietary factors and CRC are modified by genetic variation. This could have implications for primary prevention.