CHICAGO -- Scientists now believe that about one in five cancers is at least partly inherited.

On Thursday, Chicago researchers confirmed the discovery of another cancer gene that may be the most deadly yet. The hope is that the discovery will lead to earlier diagnosis, treatment, or prevention -- like what's currently being offered to women with a breast cancer gene.

It was a yearly mammogram that discovered a tiny tumor in Kathy Lambert's left breast. In a way, she'd been expecting it.

"My mother had cancer and died at 54," said Lambert (pictured, right). "And then her mother had it, and then my mom had a cousin who died at 50. So, we've always wondered when it's going to be my time to have it."

BREAST CANCER Video: New Mammogram Advice Survey: When Should Screening Start? Interactive: Survivors Share Stories Interactive: Woman Gets Tests Slideshow: Foods Fight Cancer? Slideshow: Self-Checks Help Story: Kinds Of Breast Cancer? Story: Terms Patients Need To Know Story: Breast Cancer Gene Link: Survivors On Twitter

Lambert's tumor was removed in its most curable stage. But at Northwestern Memorial Hospital in Chicago, genetics counselor Taya Young warned Lambert that her risk for more tumors remained high. She had inherited a BRCA gene for breast and ovarian cancer.

Young said that patients with BRCA I and II have up to an 87 percent risk of developing breast cancer, and up to a 44 percent risk of developing ovarian cancer.

Meanwhile, other researchers at Northwestern were confirming the existence of yet another cancer gene that's far more common -- it's in every 10th person.

"This gene is called TGEFBR1*6A. Just to shorten it, we call it 6A," said Dr. Virginia Kaklamani.

A cancer specialist, Kaklamani said the 6A mutation increases the risk of breast cancer by 48 percent, of ovarian cancer by 53 percent, and of colon cancer by 38 percent for women and men.

"In the U.S. in 2003, this gene should be responsible for more than 20,000 new cases of cancer," Kaklamani said.

But knowing about the gene now may save lives. It can lead to a new blood test for the mutation that will give patients the same early warning and the same chance to survive that Lambert had.

"There are things that we can do to reduce that risk and to make it so that they're living with a cancer risk, not dying from a cancer," Young said.

The research by Kaklamani's team is published in the Sept. 1 issue of the Journal of Clinical Oncology.

Study Abstract