773 Piwi-interacting RNAs as novel prognostic markers in clear cell renal cell carcinomas

Abstract

Background: Piwi-interacting RNAs (piRNAs) are small RNAs of 27-30 nucleotides mapping to transposons or clustering in repeat genomic regions. Preliminary studies suggest an important role in cancerogenesis. This study is the first one investigating their prognostic impact in clear cell renal cell cancer (ccRCC) patients. Methods: Three piRNAs (piR-30924, piR-57125, and piR-38756) selected on the basis of initial piRNA microarray analyses were determined using RT-qPCR in non-metastatic (n = 76) and metastatic (n = 30) ccRCC tissue at the time of nephrectomy in comparison to normal renal tissue (n = 77) and tissue from distant ccRCC metastases (n = 13). Primary clinical end points were recurrence-free and overall survival.

Circular RNAs in Clear Cell Renal Cell Carcinoma: Their Microarray-Based Identification, Analytical Validation, and Potential Use in a Clinico-Genomic Model to Improve Prognostic Accuracy

“…None of the patients received systemic therapy prior to nephrectomy. Tissue specimens were sampled immediately after nephrectomy, either snap frozen in liquid nitrogen or immersed in RNAlater solution (Qiagen, Hilden, Germany), and stored at −80 °C until analysis as described in our previous publications [61,62,63].…”

“…Total RNA was isolated from 30 to 98 mg tissue pieces. The isolation procedure from preserved tissue specimens using the miRNeasy Mini Kit (Qiagen) including an on-column DNA digestion step according to the producer's instructions, the spectrophotometric quantification (NanoDrop 1000 Spectrophotometer; NanoDrop Technologies, Wilmington, DE, USA), and the quality assessment of the total RNA samples (ratio of the absorbance at 260 nm to that at 280 nm and RNA integrity number on a Bioanalyzer 21000 (Agilent Technologies, Santa Clara, CA, USA) were detailed described in our previous publications [61,62,63]. The median ratio of 260 nm to 280 nm of the isolated RNA samples was 2.04 (95% CI, 2.03 to 2.04) and the median RNA integrity number was 7.70 (95% CI, 7.52 to 7.88).…”