miRNAs are Stable in Several Severe Storage

MicroRNAs (miRNAs) are known as small non-coding RNA molecules and down-regulator for specific mRNA expressions. In the oncology area, miRNAs play important roles such as carcinogenesis, invasion, and metastasis. To date, several studies have clarified that circulating miRNA in plasma (serum) was a potential marker for colorectal cancer detection [1,2], and was remarkably stable in plasma due to its protection from endogenous RNase activity [3]. Moreover, miRNAs can be preserved in severe storage conditions, such as fecal samples [4] and formalin-fixed paraffin-embedded (FFPE) tissues [5]. In a clinical laboratory examination related to colorectal cancer, not only blood samples but also tissue and fecal samples are used for cancer detection and screening. Thus, miRNAs extracted from these samples were useful for biomarkers for detection of colorectal cancer or prediction of tumor recurrence by using miRNA microarray and real-time RT-PCR analyses. Several miRNA analyses of colorectal cancer using fecal and FFPE samples were shown in this mini review.