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Discovery of New Cancer Genes Offers Hope for More Effective Treatments

Scientists studying human cancer genes have identified new mutations that may offer clues about what triggers cancer to form malignancies. As VOA's Jessica Berman reports, the geneticists say their work will finally give cancer researchers a better idea of what they are up against.

Scientists at the Wellcome Trust Sanger Institute in London say they found more than 100 new mutations as they deciphered 500 genes in a family of proteins known as kinases.

Kinases have been implicated in human cancers because they regulate the behavior of cells, such as telling them when to live, die or divide. Cancer cells do not respond to the body's normal signals to die, and they grow out of control.

In the study published in the journal Nature, researchers sequenced kinases in a range of cancers, including breast, lung, colorectal and stomach cancers.

Mike Stratton is co-investigator of the cancer genome project at the Wellcome Trust Sanger Institute in London. He says researchers found approximately 1,000 mutations in the DNA of the cancer cells they sequenced.

"When we analyzed those 1,000 mutations in more detail, what we find is quite surprising," he said. "Because we found evidence for really quite a large number of new cancer genes. We found evidence for approximately 100 new cancer genes from within those 1,000 mutations."

Genetic mutations are structural alterations in the code of DNA that regulates normal cellular functioning.

Stratton and colleagues divided the 100 new cancer genes into "passenger" or "driver" genes. The passengers greatly outnumbered the drivers, and had mutations that did not contribute to cancer in any significant way. The drivers, on the other hand, caused cells to begin acting abnormally, a feature of cancer.

Stratton says some aggressive cancers, like testicular cancer, have one or two mutations, while others, like lung cancer, have many.

"Mutations that you find in cancer are like an archaeological record of what that cancer has been through in its lifetime," he noted. "So, the mutations can tell you about an exposure that that cancer cell has been through 25 years, decades before."

Stratton says the work will allow scientists to interpret the factors that led to a cancer, such as ultraviolet light. But other exposures, such as unknown environmental chemicals or abnormalities of the body's cellular repair mechanism, may be harder to find.

Co-investigator Andy Futreal says the study gives cancer researchers a more comprehensive view of the genetic changes that cause the disease in each of its different forms. And he says that is likely to lead to the development of new and more effective drugs to treat cancer.

But Futreal concedes researchers have only scratched the surface in their quest for cancer genes, since the kinases make up approximately one percent of the human genome.

"We need to expand the numbers of tumors, the numbers of genes sequenced, the numbers of types of tumors," he added. "So, I think it is all moving in the right direction."

The scientists expect that new, faster technologies to find DNA sequencing will help them expand their search for cancer mutations within the human genome.