The Insect Shield Repellent Apparel - bandanna $8-$12, shirt $80 - available from L.L.Bean, Orvis and other outdoor brands has a key ingredient of Permethrin, which is a man-made version of natural repellent found in chrysanthemum flowers. (Peter Andrew Bosch/Miami Herald/MCT)

RALEIGH, N.C. — A Duke University study has enhanced scientists' understanding of what makes breast cancer in younger women so different from breast cancer in older women.

The results provide further evidence for genetic factors as primary contributors to young women's tumor development, which could help researchers develop better and more targeted therapies to treat young breast cancer patients, defined as age 45 or under.

Researchers also found that tumors in older women, defined as age 65 or above, are linked to a wider pool of possible causes.

"Older women's cells have survived longer than younger women's cells, and in the process, they have been subjected to a larger number of things that could contribute to cancer development," said Dr. Kimberly Blackwell, the study's senior investigator and Duke University Medical Center breast oncologist. "It makes sense there would be a more limited set of things that are contributing to young women's tumors. The result implies some influence in the younger women who develop breast cancer that hits the cells that develop the cancer harder."

This influence tends to be related to underlying genetic problems, she added. "It could be genetic mutation from diet, nutrition, environmental exposure."

The study, funded by the National Cancer Institute and published today in the Journal of Clinical Oncology, found that the underlying difference between older and younger women's tumors was that younger women's tumors all looked pretty much the same genetically, whereas older women's were all different.

Cholesterol drugs for kids win support

CHICAGO — For the first time, an influential doctors group is recommending that some children as young as 8 be given cholesterol-fighting drugs to ward off future heart problems.

It is the strongest guidance given on the issue by the American Academy of Pediatrics, which released its new guidelines Monday. The academy also recommends low-fat milk for 1-year-olds and wider cholesterol testing.

Dr. Stephen Daniels, of the academy's nutrition committee, says the new advice is based on mounting evidence showing that damage leading to heart disease, the nation's leading killer, begins early in life. It also stems from recent research showing that cholesterol-fighting drugs are generally safe for children, he said.

Drug treatment generally would be targeted for kids at least 8 years old who have too much LDL, the "bad" cholesterol, along with other risky conditions, including obesity and high blood pressure. For overweight children with too little HDL, the "good" cholesterol, the first course of action should be weight loss, more physical activity and nutritional counseling, the academy says.

— From wire reports