The Role of the Dysregulation of Long Non-Coding and Circular RNA Expression in Medulloblastoma: A Systematic Review

SIMPLE SUMMARY: The role of long non-coding and circular RNAs in medulloblastoma, the most prevalent cerebral childhood cancer, has been widely studied from distinct perspectives, such as for the identification of potential biomarkers for diagnosis or prognosis. Moreover, their precise involvement in the origin and progression of the disease was one of the milestone discoveries regarding these molecules. New multi-omic techniques have enabled researchers to advance in the knowledge of medulloblastoma, adding complexity to the matter. Therefore, it is necessary to perform an update on all the evidence in the study of non-coding RNAs in this pathology. In this systematic review, we aimed to extract conclusions regarding the role of long non-coding and circular RNAs as biomarkers in medulloblastoma through the revision of the literature about their expression patterns and functional implications. ABSTRACT: Medulloblastoma (MB) is the most common malignant brain tumor in childhood. Although recent multi-omic studies have led to advances in MB classification, there is still room for improvement with regard to treatment response and survival. Therefore, identification of new and less invasive biomarkers is needed to refine the diagnostic process and to develop more personalized treatment strategies. In this context, non-coding RNAs (ncRNAs) could be useful biomarkers for MB. In this article, we reviewed the role of two types of ncRNAs, long non-coding (lncRNAs) and circular RNAs (circRNAs), as biomarkers for the diagnosis, subgroup classification, and prognosis of MB. We also reviewed potential candidates with specific functions and mechanisms of action in the disease. We performed a search in PubMed and Scopus using the terms (“long non coding RNAs” OR ”lncRNAs”) and (“circular RNAs” OR ”circRNAs”) AND ”medulloblastoma” to identify biomarker discovery or functional studies evaluating the effects of these ncRNAs in MB. A total of 26 articles met the inclusion criteria. Among the lncRNAs, the tumorigenic effects of the upregulated lnc-IRX3-80 and lnc-LRRC47-78 were the most studied in MB. Among the circRNAs, the upregulation of circSKA3 and its functional impact in MB cell lines were the most consistent results, so this circRNA could be considered a potential biomarker in MB. Additional validation is required for many deregulated lncRNAs and circRNAs; therefore, further studies are warranted.