I suggest you to use miRNAesy Mini Kit (qiagen). After you homogenize well the tissue (I usually use liquid nitrogen to freeze the sample) you can follow the qiazol extraction due to manufacturer instructions. This kit permit to isolate also the microRNAs
You can use trizol method to islate RNA. I have recently used this method to isolate RNA from breast cancer cell lines like, MDAMB-231, T47D, MCF-7 and normal breast cell line MCF10a.
Hi, I agree with Anna about the performance of the miRNAeasy kit (Qiagen), which allows you to obtain total RNA, and include a step for enrichment of small RNAs (