Gene activity is dependent on how well one or both genes of a pair functions. For example, the BCRA1 gene is a suppressor gene. Faulty functioning of this gene is associated with the development of an inherited form of breast cancer. If both BRCA1 genes of this pair are normal in structure and location, the woman is at normal risk for the development of breast cancer. However, if a woman inherits one mutated gene and one normal gene, her risk for development of breast cancer increases by as much as 50%. If she inherits two faulty BRCA1 genes, her risk for development of breast cancer may increase to almost 100% ( Ecsedy & Hunter, 2002 ;Rettig & Sawicki, 2001 ). For other types of cancer, a familial tendency may be noted, but no specific pattern of inheritance is evident.