The breast cancer (BC) risk of women with germline mutations of BRCAl or 2 or other high penetrance genes is dramatically increased especially at young ages. Dietary and other modifiable life-style factors, however, may influence the early occurrence of BC in mutation carriers. Fruit and vegetable, vitamin E, soy products and low glycaemic index food, as well as a low index of abdominal obesity, have been suggested to confer greater protection against hereditary BC than against sporadic BC. Mechanistic explanations include hormonal effects of diet and antioxidant protection in women with impaired DNA repair. This CASE-ONLY STUDY aims at testing exposure in patients with and without genetic predisposition, as established through family history or genetic testing. The study base will comprise over 5.000 patients who got BC before the age of 40.
MAIN OBJECTIVE: To investigate the interaction between genetic susceptibility and dietary factors in the occurrence of breast cancer (BC) ill young women.
MAIN EXPECTED ACHIEVEMENT: To establish whether there are perspectives for reducing heritable BC risk through dietary modifications, to quantify their potential effect, and to develop strategies for preventive counselling. Germline mutations of BC genes such as BRCAl and 2 confer very high lifetime risk of developing BC . Several mutations carriers, however, do not develop BC at all or develop it only late in life. It is reasonable to hypothesise, therefore, that the penetrance of the genetic trait may be regulated through other genetic or non-genetic factors. The confirmation of an association of modifiable environment factors with the penetrance of BC genes would help establishing priorities for preventive trials and would open a new perspective for genetic counselling.
- Establishment of the COS Working Group and election of a Steering Committee
- Agreed protocol and questionnaires
- Data base of patients recruited
- Software for classifying families
- Paper on "Selecting families for genetic susceptibility testing"
- Systematic case-only analyses of gene-environment interactions
- Scientific paper(s) on the effects of diet on the expression of BRCA genes
- Final workshop and planning of further studies.