title: Circulating microRNAs in cancer: Hope or hype?
abstract: Circulating miRNAs are a novel class of stable, minimally invasive disease biomarkers that are considered to be valuable in diagnosis, prognosis and treatment response monitoring. Unlike intracellular miRNAs, circulating miRNAs are released from their producer cells and, based on their targeted functions, they may shuttle in and out of circulation. Their discovery has opened up new avenues for clinical realms and led to a quest for targeted biomarkers. Subsequently, as more cell-free miRNAs are being discovered, their expression is expected to provide precise information regarding disease progression and treatment outcomes, thereby fostering personalized therapeutic strategies. The significance of circulating miRNAs capitalizes on the fact that they are highly stable in body fluids and their expression levels can be detected by common techniques such as qPCR and microarray. However, discrepancies have started to emerge in terms of their reliability and their response under physiological and pathological conditions. Functional studies are still pending, which may determine whether circulating miRNAs play a role as a central component or just as an auxiliary tuner. Also, the distinct clinical signatures that they display have never been subjected to an extensive critical review and experimental validation. As a consequence, the applicability of circulating miRNAs remains a matter of deliberation, despite many intriguing perspectives about their competency. In this review, we highlight some ambiguous issues with the application of circulating miRNAs, which may warrant an immediate consideration. We propose that the circulating miRNA domain needs to be reevaluated to authenticate their specific role and to probe whether they actually carry any clinical weightage.
authors.affiliation: Department of Radiation Oncology, James Cancer Hospital and Solove Research Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA.
authors.forename: Rajbir
authors.initials: R
authors.lastname: Singh
authors.affiliation: Department of Radiation Oncology, James Cancer Hospital and Solove Research Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA.
authors.forename: Brinda
authors.initials: B
authors.lastname: Ramasubramanian
authors.affiliation: Department of Radiation Oncology, James Cancer Hospital and Solove Research Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA.
authors.forename: Suman
authors.initials: S
authors.lastname: Kanji
authors.affiliation: Department of Radiation Oncology, James Cancer Hospital and Solove Research Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA.
authors.forename: Arup R
authors.initials: AR
authors.lastname: Chakraborty
authors.affiliation: Department of Radiation Oncology, James Cancer Hospital and Solove Research Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA.
authors.forename: Saikh Jaharul
authors.initials: SJ
authors.lastname: Haque
authors.affiliation: Department of Radiation Oncology, James Cancer Hospital and Solove Research Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA. Electronic address: arnab.chakravarti@osumc.edu.
authors.forename: Arnab
authors.initials: A
authors.lastname: Chakravarti
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000097:blood* / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D035683:MicroRNAs / Q000097:blood* / Q000235:genetics / Q000627:therapeutic use; D025202:Molecular Diagnostic Techniques; D009369:Neoplasms / Q000097:blood* / Q000235:genetics / Q000473:pathology / Q000628:therapy; D011237:Predictive Value of Tests; D011379:Prognosis; D012334:RNA, Neoplasm / Q000097:blood* / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D035683:MicroRNAs; D012334:RNA, Neoplasm
keywords: Biomarkers; Cancer; Circulating miRNA; Specificity; Translation