Some three dozen local families may hold the key to reducing deaths from hereditary breast and ovarian cancers.

An audience of about 80 people, mostly women, were educated yesterday on the role of genetics in the development of breast and ovarian cancers at the Bermuda Underwater Exploration Institute.

Cancer expert Dr. Kevin Hughes, who is overseeing a study on locals who have been diagnosed with breast cancer over a 20 year period, said that 100 out of almost 400 women had been identified as being likely to have a genetic defect which caused their cancer and they all belonged to 36 families.

Most cases of breast and ovarian cancer are not caused by hereditary factors, but genetic screening to identify a mutated gene could point the way forward to preventing the onset of cancer.

The defect greatly increases the risk of developing breast or ovarian cancer in women, and moderately increases the risk of breast and prostate cancer in men.

Dr. Hughes explained that the study's next step is to obtain additional information from those families and inform them that their risk of hereditary breast or ovarian cancer is high and take their guidance as to how they wish to proceed.

"Once we get the information to the families we want to help them inform their family members. But they are not on their own," Dr. Hughes said.

He, and colleagues, Dr. Jennifer Ligibel and local oncologist, Dr. Jean Walters explained that genetic screening was a personal decision and a number of factors had to be taken into account before making a decision.

But the response of the families, not all of whom will test positive for the defective gene, could well set the stage for how the Island as a whole deals with hereditary cancer.

"What we are looking at is five to ten person of breast or ovarian cancer in your country is probably hereditary," said Dr. Hughes. "The majority of that cancer would probably be within a small group of families... We could potentially decrease the breast cancer death rate or the development of breast cancer or ovarian cancer by five to ten percent, which may not seem like a lot, but it's a significant number of people. But also we are looking at decreasing the risk of very young breast cancer. So we might decrease breast cancer overall by ten percent, but decrease breast cancer in women in their twenties or thirties by twenty or thirty percent."

Genetic testing for these cancers was becoming less problematic, since it began in 1995, said Dr. Hughes. "But it's not trivial by any means. And absolutely the society has to decide what it wants to do, the family has to decide and the individual has to decide."