title: Hypermethylation-Associated Silencing of miR-125a and miR-125b: A Potential Marker in Colorectal Cancer.
abstract: BACKGROUND
  MicroRNAs (miRNAs) have been found to be downregulated in human colorectal cancer (CRC), and some of them may function as tumor suppressor genes (TSGs). Aberrant methylation triggers the inactivation of TSGs during tumorigenesis.
  
  
  METHODS
  We investigated the methylation status of miR-125 family in CRC tissues and adjacent nontumor tissues by using bisulfite sequencing PCR (BSP). The expression levels of the two miRNAs were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results. The methylation frequency of miR-125a and miR-125b was higher in CRC tissues. QRT-PCR analysis showed that miR-125a and miR-125b were significantly downregulated in CRC tissues. Moreover, the expression levels of miR-125a and miR-125b were inversely correlated to CpG island methylation in CRC.
  
  
  CONCLUSIONS
  Our results suggest that DNA hypermethylation may be involved in the inactivation of miR-125a and miR-125b in CRC, and hypermethylation of miR-125 is a potential biomarker for clinical outcome.
authors.affiliation: Department of Gastroenterology, People's Hospital of Taizhou, 399 Hailing Road, Taizhou, Jiangsu 225300, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Gastroenterology, People's Hospital of Taizhou, 399 Hailing Road, Taizhou, Jiangsu 225300, China ; Department of Gastroenterology, Second Xiangya Hospital, Central South University, 139 Renmin Middle Road, Changsha, Hunan 410011, China.
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Xu
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018899:CpG Islands; D019175:DNA Methylation; D005260:Female; D020868:Gene Silencing; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged
chemical_list: D014408:Biomarkers, Tumor; C531888:MIRN125 microRNA, human; D035683:MicroRNAs