Hi Ildiko, 

It depends on how you plan to extract the RNA. The kits I have experience with all have as one of their first steps the immersion of your tissue sample in a lysis buffer and the cell walls simply dissolve from the chaotropic salts. Qiagen Allprep DNA/RNA kit has the RLT buffer and there are well-tested protocols for study of RNA from urine samples. MirVana also have a decent protocol - see 

Curated MicroRNAs in Urine and Blood Fail to Validate as Predictive Biomarkers for High-Risk Prostate Cancer, PLoS ONE 9(4): e91729. 

for an example (alter the protocol according to your needs).

Good luck!

Matt

Hi Matt,

Thank you for your advice. I tried lot of RNA isolation methods for my problem. 

So my new method, first time I separate the prostate epithelial cell from urine, and I isolate RNA from prostate cell. This method is successful!

The gene of intrest in me shows low expression, but I try to amplify the RNA, and after that was syntetized cDNA.

I'm working in this project :)

Ildi