AsanewlydiscoveredtypeofRNA,circularRNAs(circRNAs)arewidespreadthroughouttheeukaryoticgenome.TheexpressionofcircRNAsisregulatedbybothcis-elementsandtrans-factors,andtheexpressionpatternofcircRNAsiscelltype-anddiseasespecific.Similartoothertypesofnon-codingRNAs,functionsofcircRNAsarealsoversatile.CircRNAshavebeenreportedpreviouslytofunctionasmicroRNA(miRNA)sponges,proteinsponges,codingRNAsorscaffoldsforproteincomplexes.Recently,severalcircRNAshavebeenreportedtoplayimportantrolesinhumanmalignancies,includingglioma.Here,wereviewedseveralreportsrelatedtocircRNAsandglioma,aswellasthepotentialdiagnosticandtherapeuticapplicationsofcircRNAsinbraincancer.Ingeneral,somecircRNAs,suchascircSMARCA5andcircCFH,arefoundtobeexpressedinagliomaspecificpattern,thesecircRNAsmaybeusedastumorbiomarkers.Inaddition,somecircRNAshavebeenfoundtoplayoncogenicrolesinglioma(e.g.,circNFIXandcircNT5E),whereasothershavebeenreportedtofunctionastumorsuppressors(e.g.,circFBXW7andcircSHPRH).Furthermore,circRNAisagoodtoolforproteinexpressionbecauseofitshigherstabilitycomparedtolinearRNAs.Thus,circRNAsmayalsobeanidealchoiceforgene/proteindeliveryinfuturebraincancertherapies.TherearesomechallengesincircRNAresearchingliomaandotherdiseases.ResearchrelatedtocircRNAsingliomaiscomparativelynewandmanymysteriesremaintobesolved.
