Results of an ongoing study expand the understanding of the mechanisms that control melanoma brain metastasis by showing several microRNAs (miRNAs) that are important mediators of metastasis.

These findings, presented in full at the American Association for Cancer Research's101st Annual Meeting 2010, may suggest potential new therapeutic targets.

"Specific components of the miRNA brain signature could have prognostic potential, and be able to identify at early stages of the disease melanoma patients at higher risk of developing brain metastasis," said Eva M. Hernando, Ph.D., Assistant professor in the department of pathology and co-director of the M.D./Ph.D. programme at NYU School of Medicine and member of the NYU Cancer Institute.

Patients with melanoma brain metastasis have a poor survival rate and are often excluded from clinical trials. There is currently no effective treatment for this devastating malignancy, according to Hernando.

Since little is known about the molecular mechanisms that govern this cancer's spread to the brain, Hernando and colleagues investigated the role for specific miRNAs in vitro and in vivo in the mediation and facilitation of melanoma brain metastasis in mice.

"Our study sheds light on previously unexplored mechanisms of miRNAs' role in the mediation of melanoma brain tropism," said Hernando.

While some miRNAs increased the metastatic potential of melanoma cells and the cells' ability to adhere to brain endothelial cells, other miRNAs contributed to the ability of the cells to invade the brain through the blood-brain barrier, according to Hernando. Alterations in another miRNA increased the ability of melanoma cells to reach the brain in mice.

"Over the past few years, more and more reports have shown significant and important roles for miRNAs in normal physiological processes and in several pathologies including cancer," said Hernando. "It was not surprising that miRNAs played a functional role in this process. However, we were pleasantly surprised to learn that our miRNA signature was validated in an independent cohort of samples."

Source: The American Association for Cancer Research