microRNA (
miRNA) based
biomarkers have unique advantages due to their critical regulatory function, superior stability, and relatively small number compared to mRNAs. A number of
miRNAs play key roles in
colon cancer stem cell chemoresistance and have clinical potential as prognostic
biomarkers. The purpose of this study is to systematically validate the prognostic potential of
miRNAs in
colorectal cancer. In this study, we validated the prognostic potential of a panel of
miRNAs using 205 stage II, III, and IV
colorectal cancer specimens by qRT-PCR analysis. We cross validated our results using The
Cancer Genome Atlas (TCGA) database. Many of the
miRNAs we investigated have been functionally validated to be important in contributing to chemoresistance to
5-fluorouracil (5-FU) based
chemotherapy. We determined that miR-16 is the most consistent
miRNA for expression normalization in
colorectal cancer. We have validated several
miRNAs (miR-15b, miR-215, miR-145, miR-192, let-7g) that are significantly associated with progression free survival (PFS) and/or overall survival (OS) of
colorectal cancer patients independent of
tumor stage and age at diagnosis. These 5
miRNAs are significantly associated with OS of
colorectal cancer even after
tumor location (left side vs. right side) is adjusted for. Furthermore, the prognostic value of let-7g for overall survival was independently validated using the
RNA-Seq results from TCGA
colorectal cancer database. These results, taken together, establish a solid foundation towards
miRNA based precision management of
colorectal cancer.