title: Study of circulating microRNA-125b levels in serum exosomes in advanced melanoma.
abstract: BACKGROUND
  Malignant melanoma is an aggressive tumor that produces exosomes, which contain microRNAs (miRNAs) that could be of utility in following tumoral cell dysregulation. MicroR-125b is a miRNA whose down-regulation seems to be implicated in melanoma progression.
  
  
  OBJECTIVE
  To analyze miR-125b levels in serum, and in exosomes obtained from serum, from patients with advanced melanoma.
  
  
  METHODS
  Serum samples were obtained from 21 patients with advanced melanoma, from 16 disease-free patients with melanoma, and from 19 healthy volunteers. Exosomes were isolated from serum by precipitation, and miR-16 and miR-125b levels were quantified by real-time polymerase chain reaction.
  
  
  RESULTS
  MicroR-16, but not miR-125b, was detected in all samples, and miR-16 levels were significantly higher in serum than they were in exosomes. MicroR-16 expression levels did not differ significantly between the 2 groups (patients with melanoma and healthy donors). There was a significant relationship between miR-125b and miR-16 levels in exosomes. Additionally, miR-125b levels in exosomes were significantly lower in patients with melanoma compared with disease-free patients with melanoma and healthy controls.
  
  
  CONCLUSIONS
  Exosomes can provide a suitable material to measure circulating miRNA in melanoma, and miR-16 can be used as an endogenous normalizer. Lower levels of miR-125b in exosomes obtained from serum are associated with advanced melanoma disease, probably reflecting the tumoral cell dysregulation.
authors.affiliation: From the Laboratory of Biochemistry (Drs Alegre and González and Ms Rodriguez) and the Department of Medical Oncology (Drs Sanmamed and Martín-Algarra and Dr Carranza), University Clinic of Navarra, Pamplona, Navarra, Spain.
authors.forename: Estibaliz
authors.initials: E
authors.lastname: Alegre
authors.forename: Miguel F
authors.initials: MF
authors.lastname: Sanmamed
authors.forename: Carmen
authors.initials: C
authors.lastname: Rodriguez
authors.forename: Omar
authors.initials: O
authors.lastname: Carranza
authors.forename: Salvador
authors.initials: S
authors.lastname: Martín-Algarra
authors.forename: Alvaro
authors.initials: A
authors.lastname: González
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood / Q000235:genetics; D016022:Case-Control Studies; D015536:Down-Regulation; D055354:Exosomes / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000097:blood* / Q000235:genetics* / Q000556:secondary; D035683:MicroRNAs / Q000097:blood* / Q000235:genetics*; D008875:Middle Aged; D012334:RNA, Neoplasm / Q000097:blood / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; C531888:MIRN125 microRNA, human; C505362:MIRN16 microRNA, human; D035683:MicroRNAs; D012334:RNA, Neoplasm