Background: Our study aimed to evaluate the clinical utility of detecting plasma
microRNAs (miR-21 & miR-92a) for diagnosis of colorectal cancer patients and its
relation to tumor staging. Patients and Methods: Quantitative real-time RT-PCR was
applied to determine the relative expression level of miR-21 and miR-92a in serum.
The sensitivity and specificity of these markers were evaluated by receiver operating
characteristic (ROC) curve analysis. Final staging of colorectal cancer cases was
assigned according to results of histopathologic examination of surgically resected
specimens. Results: This study included 52 cases of colorectal cancer (CRC), 20 cases
of precancerous colorectal lesions, and 20 healthy controls. Both Plasma miR-21 and
Plasma miR-92a were significantly higher in CRC group compared to both the control
group and precancerous group. Also, they were significantly higher in advanced CRC
stages than early CRC stages. The sensitivity and specificity of miR-21 for
discriminating CRC from controls were found to be 90.38% and 100.0%, respectively.
However, for miR-92a, sensitivity and specificity were found to be 94.23% and
100.0%, respectively. For discriminating CRC cases from precancerous lesions, the
sensitivity and specificity of miR-21 were found to be 75.08% and 95.0%,
respectively. However, for miR-92a, sensitivity and specificity were found to be
80.77% and 100.0%, respectively. Conclusions: both plasma miR-21 and miR-92a
have significant value for early detection of CRC as non-invasive screening molecular
biomarkers with high sensitivity and specificity. They also help for differentiation
between patients with benign and malignant colorectal lesions and those with early
and advanced CRC.