Emerging microRNAs in cancer diagnosis, progression, and immune surveillance.

MicroRNAs (miRNAs) are small noncoding RNAs that function in post-transcriptional regulation of gene expression. Dysregulation of miRNAs has been reported in different stages of cancer development and progression. This dysregulation results in different miRNA profiles between cancer and normal tissues. Many studies have shown a significant correlation between miRNA profile and cancer diagnosis and prognosis. Additionally, since a single miRNA regulates multiple mRNA targets, miRNAs dysregulation can affect several pathways involved in cancer development. Finally, due to their regulatory role in immune cell development, many recent studies have reported that certain miRNAs play key roles in cancer immunology. In this brief review, we discuss the role of miR-21 and miR-375 in the RAS pathway as well as their role in cancer diagnosis and progression, along with the role of other select miRNAs in cancer immune surveillance.