title: MiRNA-21 Expression Decreases from Primary Tumors to Liver Metastases in Colorectal Carcinoma.
abstract: OBJECTIVE
  Metastasis is the major cause of death in colorectal cancer patients. Expression of certain miRNAs in the primary tumors has been shown to be associated with progression of colorectal cancer and the initiation of metastasis. In this study, we compared miRNA expression in primary colorectal cancer and corresponding liver metastases in order to get an idea of the oncogenic importance of the miRNAs in established metastases.
  
  
  METHODS
  We analyzed the expression of miRNA-21, miRNA-31 and miRNA-373 in corresponding formalin-fixed paraffin-embedded (FFPE) tissue samples of primary colorectal cancer, liver metastasis and healthy tissues of 29 patients by quantitative real-time PCR.
  
  
  RESULTS
  All three miRNAs were significantly up-regulated in the primary tumor tissues as compared to healthy colon mucosa of the respective patients (p < 0.01). MiRNA-21 and miRNA-31 were also higher expressed in liver metastases as compared to healthy liver tissues (p < 0.01). No significant difference of expression of miRNA-31 and miRNA-373 was observed between primary tumors and metastases. Of note, miRNA-21 expression was significantly reduced in liver metastases as compared to the primary colorectal tumors (p < 0.01).
  
  
  CONCLUSIONS
  In the context of previous studies demonstrating increased miRNA-21 expression in metastatic primary tumors, our findings raise the question whether miRNA-21 might be involved in the initiation but not in the perpetuation and growth of metastases.
authors: Division of Molecular & Experimental Surgery, Clinic of Surgery, Friedrich-Alexander- Universität Erlangen-Nürnberg, Schwabachanlage 12, 91054, Erlangen, Germany.
authors: Fabian
authors: F
authors: Feiersinger
authors: Clinic of Urology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Krankenhausstr. 12, 91054, Erlangen, Germany.
authors: Elke
authors: E
authors: Nolte
authors: Clinic of Urology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Krankenhausstr. 12, 91054, Erlangen, Germany.
authors: Sven
authors: S
authors: Wach
authors: Department of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Krankenhausstr. 12, 91054, Erlangen, Germany.
authors: Tilman T
authors: TT
authors: Rau
authors: Clinic of Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Krankenhausstr. 12, 91054, Erlangen, Germany.
authors: Nikolaos
authors: N
authors: Vassos
authors: Department of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Krankenhausstr. 12, 91054, Erlangen, Germany.
authors: Carol
authors: C
authors: Geppert
authors: Division of Molecular & Experimental Surgery, Clinic of Surgery, Friedrich-Alexander- Universität Erlangen-Nürnberg, Schwabachanlage 12, 91054, Erlangen, Germany.
authors: Andreas
authors: A
authors: Konrad
authors: Clinic of Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Krankenhausstr. 12, 91054, Erlangen, Germany.
authors: Susanne
authors: S
authors: Merkel
authors: Clinic of Urology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Krankenhausstr. 12, 91054, Erlangen, Germany.
authors: Helge
authors: H
authors: Taubert
authors: Division of Molecular & Experimental Surgery, Clinic of Surgery, Friedrich-Alexander- Universität Erlangen-Nürnberg, Schwabachanlage 12, 91054, Erlangen, Germany.
authors: Michael
authors: M
authors: Stürzl
authors: Clinic of Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Krankenhausstr. 12, 91054, Erlangen, Germany.
authors: Roland S
authors: RS
authors: Croner
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D015536:Down-Regulation; D005260:Female; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000556:secondary*; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging
chemical_list: C524940:MIRN21 microRNA, human; D035683:MicroRNAs