Researchers have discovered a protein that appears to halt the growth of the deadly skin cancer melanoma.

In examining what makes ordinary moles different from melanomas on a genetic level, scientists at the Howard Hughes Medical Institute in Maryland discovered a series of genes, along with a genetically secreted protein, that seem to play an integral role in shutting down melanoma cells.

Melanomas develop from pigment-producing cells called melanocytes. One oncogene, BRAF, regulates the melanocytes' development into cancer through the support of other genes. BRAF is part of a signalling system that shows the cell is proliferating or dividing.

If BRAF's regulation mechanism is somehow blocked, cancer occurs.

In lab tests, the researchers identified seventeen genes that were needed by the BRAF protein to cause cell suicide. They also discovered a secreted protein, insulin-like growth factor binding protein 7 (IGFBP7), which seemed to be released when a melanocyte began expressing BRAF. The protein seemed to cause the cancer cell to begin hibernating or to die.

When researchers exposed melanoma cells in the lab to IGFBP7, they all died. As well, when mice with melanoma tumours were administered IGFBP7, the growth of their tumour cells was halted.

"It's an extremely powerful anti-cancer mechanism," said Michael Green, an investigator with Howard Hughes Medical Institute, in a release.

The study is published in the Feb. 8 issue of the journal Cell.

According to the Canadian Cancer Society, it's estimated that 4,600 Canadians developed melanoma in 2007.