In many studies, performed to investigate the genes and gene products that drive the metastatic process, it has become evident that, in addition to alterations in protein-encoding genes, abnormalities in non-coding genes can also contribute to cancer pathogenesis. In the context of microRNAs in tumours, our aim was to evaluate whether pro- metastatic and non-metastatic sarcoma cells may differ in their microRNA expression, in the effort to identify single pro-metastatic microRNAs in bone and soft-tissue sarcomas. A number of microRNAs reported in the miRNA registry data base were found to be differential expressed in MG-63 and 143B osteosarcoma model cell lines. Two of the differentially expressed microRNA, miR-93 and miR- 210, for which no functional data were available, were analyzed in different cell lines and tissues and investigated for their potential involvement in motility phenomena. The expression of another set of four differentially...