NIH Radio

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Brief Description:

A major cause of melanoma is thought to be overexposure to the sun. The ultraviolet radiation in sunlight can damage DNA and lead to cancer-causing genetic changes in skin cells. New genetic analysis of key group of enzymes may pave way for more individualized treatments.

Transcript:

Akinso: Researchers from the National Institutes of Health have identified a gene that suppresses tumor growth in melanoma, the deadliest form of skin cancer. Dr. Yardena Samuels from the National Human Genome Research Institute’s Cancer Genetics Branch explains how tumor suppressor genes work.

Samuels:Tumor suppressor genes encode proteins that normally serve as a brake on cell growth. And so when such genes are mutated or genetically altered the break maybe lifted resulting in the runaway of cell growth known as cancer.

Akinso: The NIH analysis found that one-quarter of human melanoma tumors had genetic changes in key enzymes.

Samuels: What we did was a genetic analysis of a group of enzymes called a matrix metalloproteinases or MMPs for short. These have been shown to be implicated in tumor growth in a variety of cancer types in the past. We systematically looked into these genes that encode enzymes and we found out that about a quarter of human melanoma tumors have changes or mutations in genes that code for these enzymes and importantly we found a tumor suppressor gene.

Akinso: Researchers have spent decades pursuing MMPs as promising targets for cancer therapies.

Samuels: Because members of this family were thought to be oncogenes meaning they activate growth and researchers have spent many years pursuing these enzymes as promising targets for cancer therapy—therapies that never worked. We are now showing that some of these are actually suppressing growth. And so drugs that would inhibit these MMPS are not expected to work if anything, they should fail and maybe speed up tumor growth. So this study may help explain the disappointing performance of some of these drugs used in clinical trials in the past.

Akinso: Dr. Samuels adds that the findings could lay the foundation for more individualized cancer treatment strategies where MMP and other key enzymes play a functional role in tumor growth and spread of the disease. This is Wally Akinso at the National Institutes of Health, Bethesda, Maryland.