Background: Colorectal cancer (CRC) is a major cause of cancer-related death and cancer-related incidenceworldwide. The potential of microRNA-21 (miR-21) as a biomarker for CRC detection has been studied inseveral studies. However, the results were inconsistent. Therefore, we conducted the present meta-analysis tosystematically assess the diagnostic value of miR-21 for CRC. Materials and
Methods: Using a random-effectmodel, the pooled sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio(NLR), and diagnostic odds ratio (DOR) were calculated to evaluate the diagnostic performance of miR-21 forCRC. A summary receiver operating characteristic (SROC) curve and an area under the curve (AUC) were alsogenerated to assess the diagnosis accuracy of miR-21 for CRC. Q test and I2 statistics were used to assess betweenstudyheterogeneity. Publication bias was evaluated by the Deeks’ funnel plot asymmetry test.
Results: A totalof 986 CRC patients and 702 matched healthy controls from 8 studies were involved in the meta-analysis. Thepooled results for SEN, SPE, PLR, NLR, DOR, and AUC were 57% (95%CI: 39%-74%), 87% (95%CI: 78%-93%), 4.4 (95%CI: 2.4-8.0), 0.49 (95%CI: 0.32-0.74), 9 (95%CI: 4-22), and 0.83 (95%CI: 0.79-0.86), respectively.Subgroup analyses further suggested that blood-based studies showed a better diagnostic accuracy comparedwith feces-based studies, indicating that blood may be a better matrix for miR-21 assay and CRC detection.
Conclusions: Our findings suggest that miR-21 has a potential diagnostic value for CRC with a moderate levelof overall diagnostic accuracy. Hence, it could be used as auxiliary means for the initial screening of CRC andavoid unnecessary colonoscopy, which is an invasive and expensive procedure.