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Archive - Jul 7, 2009

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Two Genes Associated with Mole Number and Melanoma Risk

Researchers from the Queensland Institute of Medical Research in Australia, and collaborators, have shown that variants in two genes (MTAP and PLA2G6) are associated with an increased number of moles and with an increased risk of melanoma, the deadliest form of skin cancer. "These are the first genes found to increase melanoma risk by influencing the number of moles a person has," explained Dr. Nick Hayward, a lead author of the study. "This finding improves our understanding of the genetics of melanoma and therefore the molecular pathways that lead to its development.” He noted that “it has long been known that having a large number of moles is the biggest risk factor. Therefore we predicted we would find genes linking moles and melanoma. We now have conclusive genetic evidence that having a large number of moles increases an individual's risk of developing melanoma." The study found that having an associated variant in one of the two genes increased the risk of melanoma by 25 percent, while having associated variants in both genes doubled the risk. Australia has the highest incidence of melanoma in the world with more than 10,000 new cases and 1,000 people dying from the disease every year. Queensland has the highest incidence of any state in Australia with seven Queenslanders diagnosed with melanoma every day. More than one in 20 Queenslanders is expected to develop melanoma during his or her lifetime. The new research was reported online in Nature Genetics on July 5. [Press release] [Nature Genetics abstract]

Prostate Cancer Homing Molecule Could Carry Imaging Agents and Therapeutics

Researchers at Purdue University and Endocyte, Inc., have synthesized a molecule that selectively targets prostate cancer cells and penetrates them. The researchers have designed the molecule so that imaging agents or therapeutic agents can be carried with it as cargo. The molecular “homing device” could improve detection and allow for the first targeted treatment of the disease, the researchers believe. "Currently none of the drugs available to treat prostate cancer are targeted, which means they go everywhere in the body as opposed to only the tumor, and so are quite toxic for the patient," said Dr. Philip Low, senior author of two papers describing the new research in the June 1 edition of Molecular Pharmaceutics. "By being able to target only the cancer cells, we could eliminate toxic side effects of treatments. In addition, the ability to target only the cancer cells can greatly improve imaging of the cancer to diagnose the disease, [and to] determine if it has spread or is responding to treatment." Prostate cancer is the most common cancer, other than skin cancers, and is the second leading cause of cancer death in American men, according to the American Cancer Society. It is estimated that about 192,280 new cases will be diagnosed and 27,360 men will die of prostate cancer in the United States this year. The new synthetic molecule attaches to prostate-specific membrane antigen (PSMA), a protein that is found on the membranes of more than 90 percent of all prostate cancers. It also is found on the blood vessels of most solid tumors and thus could also provide a way to cut off the tumor blood supply, Dr. Low said. "A lot of new drugs are being designed to destroy the vasculature of solid tumors, and, if they could be linked to this new targeting molecule, we could have a two-pronged attack for prostate cancer," he said.