Promising melanoma predictor studied

For this deadly variety of skin cancer, effective treatment continues to be bedeviled by challenges in detection.

By Victoria Stagg Elliott, AMNews staff. Sept. 10, 2001.

Mapping Disease
As the results of the Human Genome Project began to shake out into clinical applications, this 2001-02 series detailed progress in the prevention and treatment of a variety of diseases and conditions -- both on the near horizon and possibilities far into the future.

Researchers are proposing that a protein found in many early-stage melanomas may become the basis for an early diagnostic test for the cancer that kills 7,800 people annually .

The protein in question appears to deactivate a tumor suppressor gene. Its identification could improve patients' chances for early detection -- crucial because melanoma has a high cure rate if caught early. Few patients whose cancer has spread survive beyond five years.

"Melanoma is a disease that progresses very quickly, and it kills you very quickly," said Rhoda Alani, MD, assistant professor of oncology, dermatology, molecular biology and genetics at Johns Hopkins University in Baltimore.

But early diagnosis is not easy. It depends on patient alertness and the pathologist's ability to distinguish between an atypical mole and early-stage melanoma.

"If it was just considered to be an atypical mole, you wouldn't be as aggressive, so it's an important distinction to make, but not an easy one," said Dr. Alani.

According to papers published in last month's Cancer Research and the July issue of Proceedings of the National Academy of Sciences, researchers noted that a protein produced by a cell regulatory gene, Id1, deactivates the tumor suppressor gene, p16/Ink4a, and allows cancer cells to grow unchecked. The research was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases, but the work was conducted at several institutions.

Id1 is not expressed at the later stages or in precancerous or noncancerous moles. P16/Ink4a is sometimes deactivated because of genetic heritage rather than the work of Id1. Because rates of melanoma have increased rapidly in the past 10 years, with many cases not linked to family history, researchers are suggesting that a test for Id1 might become a useful marker to distinguish early-stage malignant melanoma from abnormal but otherwise benign moles. Ultimately, this could help determine who needs more aggressive treatment. [...]