title: Current State of Circulating MicroRNAs as Cancer Biomarkers.
abstract: BACKGROUND
  Numerous studies have demonstrated the existence of stable regulatory RNAs, microRNAs (miRNAs), in the circulation and have shown that the spectrum of these extracellular miRNAs is affected by various pathologic conditions including cancers.
  
  
  BACKGROUND
  Circulating miRNAs have been the focus of numerous cancer biomarker discovery efforts over the past few years; however, a considerable number of these studies have yielded inconsistent and irreproducible findings. Here, we have summarized and compared the results of studies covering 8 different cancer types to address key questions, including the possibility of using circulating miRNA to detect cancers and what factors may affect miRNA signatures. Although identifying circulating miRNA signatures to detect specific types of early stage cancers can be challenging, study results suggest that it may be possible to use miRNAs to detect cancers in general.
  
  
  CONCLUSIONS
  Circulating miRNA is a rich source for potential disease biomarkers; however, factors, both intrinsic and extrinsic, that may affect measurement of circulating miRNA have not been fully characterized. Better understanding of intra- and intercellular miRNA trafficking and the fundamental biology of cancer cell-derived lipid vesicles may facilitate the development of circulating miRNA-based biomarkers for cancer detection and classification.
authors: Institute of Medical Systems Biology, Dongguan Scientific Research Center, Guangdong Medical University, Dongguan, Guangdong, China; dr.hyq@hotmail.com kwang@systemsbiology.org.
authors: Yuqing
authors: Y
authors: He
authors: Department of Epidemiology and Medical Statistics, Guangdong Medical University, Dongguan, Guangdong, China;
authors: Juanjuan
authors: J
authors: Lin
authors: Department of Epidemiology and Medical Statistics, Guangdong Medical University, Dongguan, Guangdong, China;
authors: Danli
authors: D
authors: Kong
authors: Department of Health Inspection, Guangdong Medical University, Dongguan, Guangdong, China;
authors: Mingyuan
authors: M
authors: Huang
authors: Department of Epidemiology and Medical Statistics, Guangdong Medical University, Dongguan, Guangdong, China;
authors: Chengkai
authors: C
authors: Xu
authors: Institute for Systems Biology, Seattle, WA;
authors: Taek-Kyun
authors: TK
authors: Kim
authors: Pacific Northwest Diabetes Research Institute, Seattle, WA.
authors: Alton
authors: A
authors: Etheridge
authors: Department of Epidemiology and Medical Statistics, Guangdong Medical University, Dongguan, Guangdong, China;
authors: Yanhong
authors: Y
authors: Luo
authors: Department of Epidemiology and Medical Statistics, Guangdong Medical University, Dongguan, Guangdong, China;
authors: Yuanlin
authors: Y
authors: Ding
authors: Institute for Systems Biology, Seattle, WA; dr.hyq@hotmail.com kwang@systemsbiology.org.
authors: Kai
authors: K
authors: Wang
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000097:blood / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000097:blood* / Q000235:genetics; D009369:Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D035683:MicroRNAs