KAHULUI - Half of the United States' population of men and a third of its women will develop cancer in their lifetimes, according to the American Cancer Society.

And, while many people believe a family history of cancer or fate will determine whether they get the disease, it's now "pretty clear" that environmental and lifestyle factors, such as smoking or excessive exposure to sun, lead to most cancers - not heredity, according to Dr. Laurence Kolonel, a Harvard Medical School-trained epidemiologist and a professor of public health at the John A. Burns School of Medicine in Honolulu.

"Most people think they're doomed" because cancer runs in their families, Kolonel said. So many are surprised that fewer than 5 percent of cases of cancer stem directly from inheritance and most of those occur early in life.

While a person's genetic makeup still plays an important role in determining whether he or she will be susceptible to cancer, anyone can do much to reduce the risk by not smoking, limiting time in the sun, being physically active and eating a diet with more fruits and vegetables, Kolonel said.

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