Roughly 1 in 50 women with endometrial cancer carry the mutation for Lynch syndrome (hereditary nonpolyposis colon cancer), which also places them at higher risk for ovarian and gastric cancer, according to an article in the August 1 issue of Cancer Research.

The American study is the first to comprehensively screen a large number of women with uterine cancer for Lynch syndrome mutations, said Heather Hampel, a genetic counselor and first author of the study. The analysis showed that 1.8 percent of newly diagnosed endometrial cancer patients have mutations for Lynch syndrome, also known as hereditary nonpolyposis colon cancer, or HNPCC

“It’s important to identify women with one of these mutations because they have a very high risk for developing colon cancer, and they may not be aware of that risk,” said Hampel. “Because this is hereditary, half of her siblings and children may also be at risk for the syndrome.

“For this reason, the relatives of a person with Lynch syndrome should also be screened for the responsible gene mutation,” said Hampel, a clinical assistant professor in the department of internal medicine.

Family members who also have the mutation need close monitoring for early cancer detection, including an annual colonoscopy starting at age 25 and endometrial cancer screening with ultrasounds and biopsies starting at age 30, Hampel said.

This study involving 543 women was led by Albert de la Chapelle, co-leader of the OSUCCC Molecular Biology and Cancer Genetics Program. Participants in the study were diagnosed and treated for endometrial cancer at the three major hospital systems in Columbus, Ohio, between 1999 and 2003.

To learn the frequency of Lynch syndrome mutations among all newly diagnosed endometrial cancer patients, the researchers tested tissue from the tumors from each patient for microsatellite instability, a change in the DNA of tumor cells that occurs in more than 90 percent of Lynch syndrome tumors. Of the 543 tumors tested, 118 showed instability. Because these patients are more likely to have Lynch syndrome, they participated in the gene testing portion of the study and nine (1.8 percent) were found to have Lynch syndrome mutations.

In addition, the researchers used another technique called immunohistochemistry to prescreen tumors for mutations. Follow-up gene testing performed on patients with abnormal immunohistochemistry results showed that one additional woman without microsatellite instability also had a Lynch syndrome mutation.

Of the 10 Lynch syndrome patients, seven did not meet the usual criteria for diagnosing the hereditary condition. That diagnosis is largely based on family history and age. Ordinarily, these seven cases would have gone undiagnosed.

In addition, the counseling and testing of 21 relatives of the 10 women with Lynch syndrome revealed 10 additional people with Lynch syndrome mutations.

The study is the continuation of an Ohio State colon cancer study also led by de la Chapelle that was published in the New England Journal of Medicine in 2005. In that study, 2.2 percent of newly diagnosed colon cancer patients tested positive for Lynch syndrome.

“We think such genetic testing should be nationwide on all colon cancer and endometrial cancer patients, but further cost-benefit analysis and study is needed first,” Hampel said. “Screening for Lynch syndrome can save lives.”