BAKERSFIELD, Calif. -- In the war on cancer, scientists are battling the disease right where it begins: within tiny strands of DNA.

There are many different kinds of mutations in DNA that can cause cancer, and each specific change provides new clues about how the illness starts and potential ways to treat it.

In two new studies, British researchers found evidence that our behavior alters some genes and these changes may trigger cancers.

Doctors studying tumor cells from a man with melanoma found DNA damage caused by ultraviolet light -- and UV rays from the sun are a known risk factor for skin cancer.

Other research on lung cancer cells revealed mutations caused by carcinogens in tobacco smoke. Scientists saw evidence that the DNA had tried to repair itself but it was unsuccessful.

Experts said these findings show the interplay between our genes and our environment -- people are born with risks for certain diseases due to their genes, but then their lifestyle choices act on those same genes, changing them for the better or the worse.