I was part of a genetic research study for heredity breast cancer in the mid 1990's. at that time I was informed I did not have a BRCA gene mutation. This past year my brother was diagnosed with breast cancer and found out he did carry the BRCA2 gene mutation. At that point I decided to be retested and indeed I do carry the BRCA2 gene mutation. The results of the original study were wrong. Any insight how often this may have happened or is happening to others.