Emerging molecular mechanisms underlying cancer metastasis: the rising role of the long non-coding RNA GAS5

Metastasis is a multistep process, wherein cells in a primary tumor acquire invasive properties and disseminate throughout the body to establish secondary tumors at distant organs. During the metastatic cascade a complex interaction of signals are involved and identification of novel players in this process is crucial for cancer prognosis and for the development of agents effective on late stage malignancies. Although most of the studies in the literature focus on protein modulators of metastasis, the relevance of non-coding RNAs is now being appreciated. Long non-coding RNAs (lncRNAs) are commonly referred to as non-protein-coding RNA transcripts longer than 200 nucleotides. Emerging evidence has shown that lncRNAs are dysregulated in multiple cancer types and have a critical role in the process of metastasis (1). Of particular interest in this regard is the lncRNA GAS5 (growth arrest-specific transcript 5) which is down-regulated and inversely correlates with clinicopathological characteristics such as tumor size and metastasis progression in various human cancers, such as renal clear cells and bladder cancer (2,3). However, studies on melanoma are still scarce.