The main causes of death in osteosarcoma (OS) patients are the development of distant metastasis and resistance to chemotherapy. Clarification of the pathophysiological molecular mechanisms that contribute to the malignant phenotype in OS and identification of a molecular target, such as a diagnostic marker, prognostic predictor, or chemosensitivity sensor, are strongly desired to develop therapeutics for OS patients. Accumulating evidence has demonstrated that microRNAs (miRNAs), small endogenous single‐stranded noncoding RNAs, play critical roles not only in biological but also pathological processes such as cancer. miRNAs can function as oncogenes or tumor‐suppressive genes depending on the mRNA they target. They are strongly associated with OS invasion, metastasis, and chemoresistance as well as OS cancer stemness. Furthermore, miRNAs are associated with commonly altered genes, such as TP53 and RB1. Additionally, recent global microRNA expression analyses have identified specific miRNAs correlated with the clinical stage and the response to chemotherapy. In this chapter, we summarize the current understanding of the pathological roles of miRNAs as well as their potential utility as OS biomarkers.
Part of the book: Osteosarcoma