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Decreased expression levels of PIWIL1, PIWIL2, and PIWIL4 are associated with worse survival in renal cell carcinoma patients

Authors Iliev R, Stanik M, Fedorko M, Poprach A, Vychytilova-Faltejskova P, Slaba K, Svoboda M, Fabian P, Pacik D, Dolezel J, Slaby O

Received 27 June 2015

Accepted for publication 19 September 2015

Published 8 January 2016 Volume 2016:9 Pages 217—222


Checked for plagiarism Yes

Review by Single-blind

Peer reviewers approved by Dr Manfred Beleut

Peer reviewer comments 3

Editor who approved publication: Dr William Cho

Robert Iliev,1,2 Michal Stanik,3 Michal Fedorko,4 Alexandr Poprach,1 Petra Vychytilova-Faltejskova,1,2 Katerina Slaba,2 Marek Svoboda,1 Pavel Fabian,5 Dalibor Pacik,1 Jan Dolezel,2 Ondrej Slaby3,4

1Department of Comprehensive Cancer Care, Masaryk Memorial Cancer Institute, 2Central European Institute of Technology, Masaryk University, 3Department of Urologic Oncology, Masaryk Memorial Cancer Institute, 4Department of Urology, University Hospital Brno, Masaryk University Brno, 5Department of Diagnostic and Experimental Pathology, Masaryk Memorial Cancer Institute, Brno, Czech Republic

Abstract: Piwi-interacting RNAs (piRNAs) are a newly discovered class of small non-coding RNAs involved in silencing of transposable elements and in sequence-specific chromatin modifications. PIWI proteins (PIWIL) belong to the family of Argonaute genes/proteins, bind piRNAs and their functioning have been described mainly in germ-line cells and more recently also in stem cells and cancer cells. There are four PIWI proteins PIWIL1, PIWIL2, PIWIL3, and PIWIL4 discovered in human till now. Recent studies suggested that deregulated the expression of Piwi proteins and selected piRNAs is common to many types of cancers. We found significantly lower expression of PIWIL1 (P<0.0001) and piR-823 (P=0.0001) in tumor tissue in comparison to paired renal parenchyma. Further, we observed progressive decrease in PIWIL1 (P=0.0228), PIWIL2 (P=0.0015), and PIWIL4 (P=0.0028) expression levels together with increasing clinical stage. PIWIL2 (P=0.0073) and PIWIL4 (P=0.0001) expression progressively decreased also with increasing Fuhrman grade. Most importantly, low-expression levels of PIWIL1 (P=0.009), PIWIL2 (P<0.0001), and PIWIL4 (P=0.0065) were significantly associated with worse overall survival in renal cell carcinoma (RCC) patients. Our results suggest the involvement of PIWIL genes and piR-823 in RCC pathogenesis, and indicate PIWIL1, PIWIL2, and PIWIL4 as potential prognostic biomarkers in patients with RCC.

Keywords: kidney cancer, PIWIL, piRNA

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