Exposure expression profiles in a prospective cancer study - The Norwegian Women and Cancer postgenome cohort

From 1991 women in Norway has been recruited to participate in NOWAC by postal questionnaires. They are drawn at random from the population through the central person register. Follow-up on cancer and death is based on linkage to national registers. Altog ether 150 000 women aged 30-70 years at recruitment participate. They receive a repeteated questionnaire each 5. year. In The NOWAC study the collection of a sub-cohort consisting of about 50 000 women with a specific blood sample buffered for mRNA analys is, the postgenome cohort, will be completed summer 2006. The women are born 1943-57, or about 50-64 years in 2007. From autumn 2006 we will start collection of tumor tissue from breast cancer cases originating in the postgenome cohort in collaboration wi th all major Norwegian hospitals and the Norwegian Breast Cancer Group. Follow-up will be 4-5 years. Meanwhile we will study the expression profiles of different exposure of major interest in our study; fatty acids including omega-3, D-vitamins, exogenous and endogenous hormones and organic pollutants. We will use both biomarkers and questionnaire information as exposure measures. Based on power calculation we have started to extract RNA from 450 random samples. The analysis of the micro-array will be do ne at the FUGE platform in Tromsø and at the Department of genetics, The Norwegian Radiumhospital. Collaboration with the FUGE platform of bioinformatics in Bergen is started. All biomarkers will be measured at leading Norwegian laboratories. The project will be the start of a systematic work to create a library of exposure patterns necessary for the interpretation of the forthcoming nested case-control studies in the postgenome cohort when sufficient years of follow-up or cases has accumulated. The popul ationbased design together with the two postgenome biobanks with RNA buffered blood and tumour tissue is to our knowledge unique.