Genetic links to breast, ovarian cancer might be hidden on paternal side, study says

[Al-khiyal]

CHICAGO, June 21, 2007 -- A deadly gene‘s path can hide in a family tree when a woman has few aunts and older sisters, making it appear that her breast cancer struck out of nowhere when it really came from Dad.

Guidelines used by insurance companies to decide coverage for genetic testing should change to reflect the findings, said study co-author Dr. Jeffrey Weitzel of City of Hope Cancer Center in Duarte, California. Testing can cost more than $3,000.

Weitzel said doctors often overlook the genetic risk from the father‘s side of the family.

None of the cancer patients in the study had a family history of breast or ovarian cancer.

The researchers defined few female relatives as fewer than two on either the father‘s or mother‘s side of the family.

When such a woman gets breast cancer before age 50, she should get a genetic test, said Dr. Noah Kauff, a cancer geneticist at Memorial Sloan-Kettering Cancer Center in New York. That would help her decide whether to have the unaffected breast or her ovaries removed to prevent more cancer. Kauff was not involved in the research, but wrote an accompanying editorial.

Genetic testing helps a woman choose her next medical steps. A woman with breast cancer who has a BRCA gene mutation has a four times greater risk of developing cancer in the other breast and a 10 times greater risk of ovarian cancer than does a woman with breast cancer who has no BRCA gene mutation.

Testing the genes of more women would cost more money, but Weitzel said that won‘t add significantly to health care costs and will prevent cancer in some of the women.

Breast cancer genes can come from father

[Al-khiyal]

A study published Wednesday in the Journal of the American Medical Association found that genetic links to breast and ovarian cancers might be hidden on the paternal side and in some families where there are few female relatives, the Long Island Newsday reports.

Jeffrey Weitzel of the City of Hope cancer center in Duarte, California, and colleagues between 1997 and 2007 evaluated 306 women who were diagnosed with breast cancer before age 50 to determine if risk assessment tools used by insurance companies to dictate reimbursement for genetic screening were underestimating breast cancer risk for some women, Reuters reports. Women with two or fewer close female relatives on either side who lived past the age of 45 were considered to have a "limited family structure," according to Reuters. About 50% of the participants fell into this category.

The study found that participants with less family information to evaluate were at a higher risk of having BRCA1 or BRCA2 mutations, which are believed to increase the chance of developing breast and ovarian cancers. The mutations were found in 13.7% of participants with limited family structure, compared with 5.2% of participants with an adequate family structure. Weitzel said the findings challenge the accuracy of the probability models used to determine the need for genetic tests.

"A lot of people - doctors included - forget that [the father] can be the contributor" of the genetic mutations, and "a patient can be blinded as to what's happening on the paternal side," Weitzel said. He added, "Half of genetic breast cancers are inherited from a woman's father, not her mother. But unless [the father] has female relatives with breast cancer, the faulty gene may have been passed down silently, without causing cancer."

Weitzel said guidelines used by insurance companies to decide coverage for genetic testing should change in light of the study's findings. Noah Kauff, a cancer geneticist at Memorial Sloan-Kettering Cancer Center in New York City, in a related JAMA editorial wrote that women with few female relatives who develop breast cancer before age 50 should get a genetic test.

Genetic links to breast, ovarian cancer might be hidden on paternal side, study says

[Bent_Bladi]

Genetic testing helps a woman choose her next medical steps. A woman with breast cancer who has a BRCA gene mutation has a four times greater risk of developing cancer in the other breast and a 10 times greater risk of ovarian cancer than does a woman with breast cancer who has no BRCA gene mutation.

OMG!

[Al-khiyal]

June 21, 2007 -- Personal DNA sequences will become a routine tool in the diagnosis of diseases within 10 years, according to the father of genetics, James Watson. He said that, as the costs of the sequencing technology tumble, doctors will be able to use the information to plan more effective treatments for conditions including mental illness, cancer, obesity and diabetes.

Professor Watson, who discovered the structure of DNA in 1953 with his Cambridge University colleague Francis Crick, was speaking yesterday at the launch of the Wellcome Collection, a new national museum based in London that will examine the scientific and artistic connections between people and biomedicine.

Using current technology sequencing a single person's DNA takes 20 technicians around nine months. "In five years the hope is that you could reduce that to a week with just two or three people," said Michael Jones, head of the genomics core lab at Imperial College London. "New technologies are trying to eliminate the technicians you need. The idea is you can take someone's DNA and plug it into a machine and the data will come out."

Prof Watson said the advances would allow doctors to use DNA sequences to help with diagnosis and give advice to people with genetic diseases. "If you have a certain change that causes cystic fibrosis and if your son has one copy of it, perhaps wisdom would be that he shouldn't have children until the partner has had gene tests also," said Prof Watson. "You might warn [your children] you have a gene and they can go and sequence them."

There will also be implications for the treatment of cancer. "Ten years from now we'll realise you shouldn't treat a cancer until you've seen what's gone wrong with the DNA." He cited breast cancer as an example. A woman with defective versions of either of the BRCA genes has a risk of developing breast cancer of up to 80%. There is also an increased risk of ovarian cancer. "A woman doesn't test herself for BRCA1 unless there's a history of breast cancer in her family. But when the cost comes down, just sequence yourself."

If a woman was found to have the disease variant of the BRCA gene, she could consider having a hysterectomy after having children so that she was not also at increased risk of ovarian cancer, he said.

Paul Pharaoh, a Cancer Research UK senior fellow at Cambridge University, said that, although prophylactic surgery was an option for women with faulty genes, increased screening would only affect a small number of women because faults in BRCA genes only account for 2% of breast cancers.

Prof Watson said genetics would help tackle mental illness. At his Cold Spring Harbour Laboratory in the US, scientists have started a project to find the genetic root for every mental condition within 10 years.

Gene-screening will be norm in 10 years, says DNA pioneer