... LAUKKANEN,eDEBORAH HELLYER, a ABRAHAM REINHARTZ, a ANDREW WATTERSON,bHAKAMABU-ZAHRA,fELEANOR MATICKA-TYNDALE,cKENNETHSCHNEIDER,fMATTHIAS BECK,g AND MICHAEL GILBERTSONb a Occupational ... Occupational Classi-fication. Ottawa, Canada.16. STATISTICS CANADA. 1998. North American Industrial Classification System. Ot-tawa, Canada.17. CHECKOWAY, H., N. PEARCE &D.CRAWFORD-BROWN. ... breast cancer and mutation of the BRCA1 and BRCA2 gene, canexplain less than 10% of breast cancer cases.1Factors that increase cumula-tive estrogen load have been found to increase risk. There...