Researchers at the National Institutes of Health (NIH) have identified a gene that inhibits the growth of malignant melanoma, one of the deadliest types of skin cancer. Published in the March 29 issue of Nature? Genetics, the findings follow a systems genetic analysis of a group of enzymes associated with skin and other cancers. The NIH study found that one-quarter of melanomas have been altered (or mutated) in their genes that encode matrix metalloprotein (MMP) enzymes.MMP and other important enzymes play functional roles in tumor growth and disease spread, which lays the groundwork for the development of more personalized cancer treatment plans. Members of the MMP gene family are often considered proto-oncogenes, and many tumors express high levels of the MMP enzyme, and researchers have spent decades seeking to use MMP as the most promising target for cancer therapies. However, when MMP inhibitors were tested on patients with multiple cancers, the drugs failed to slow tumor growth and sometimes even accelerated it. This latest study may help explain why drugs designed to treat by blocking the MMP enzyme perform so poorly. Because it turns out that the MMP gene, which is most frequently mutated in melanoma, is not a proto-oncogene at all. Researchers at the National Human Genome Research Institute (NHGRI) found that MMP-8 actually acts as a cancer suppressor gene in melanoma, and that about 6% of melanoma patients have tumors that contain mutated MMP-8 genes or related tumor suppressor genes, so blocking all of them is not a sensible treatment. Research suggests that a better treatment would be to find drugs to restore or increase MMP-8 function, or to block only those MMPs that are indeed proto-oncogenes. The researchers report in the British journal Nature Genetics that the gene they found is one of the matrix metalloproteinase (MMP) genes, which was previously thought to be a cancer-causing gene, but the new study suggests it’s actually a tumor-suppressor gene. is a tumor suppressor gene.