ABSTRACT
Background: Most cancer studies focus on exploring non-invasive biomarkers for cancer detection. In the present study, we sought to investigate the expression level of microRNA-21 [miR-21], as a potential diagnostic marker, in serum and stool samples from 40 patients with colorectal cancer [CRC] and 40 healthy controls
Methods: Quantitative real-time RT-PCR was applied to determine the relative expression level of miR-21 in serum and stool. At the same time, the sensitivity and specificity of this marker was evaluated by receiver operating characteristic [ROC] curve analysis
Results: miR-21 expression levels of serum and stool were up-regulated 12.1 [P<0.05, 95% CI: 5.774-34.045] and 10.0 [P<0.05, 95% CI: 0.351-16.260] times in CRC patients, respectively, when compared to the control group. The sensitivity and specificity of miR-21 was found to be 86.05% and 72.97%, respectively [an area under the ROC curve [AUC] of 0.783]. The stool miR-21 level in CRC patients was much higher than that in the healthy controls, showing a sensitivity of 86.05% and a specificity of 81.08% [AUC: 0.829]. The expression level of miR-21 in stool was able to significantly distinguish CRC tumor, node, metastasis stages III-IV from stages I-II, with a sensitivity and specificity of 88.1% and 81.6%, respectively [AUC: 0.872]
Conclusion: The results of this study indicated that miR-21 expression levels in serum and stool can be considered as a potential diagnostic biomarker for the diagnosis of CRC patients. However, more studies are required to confirm the validity of miR-21 as a valuable non-invasive diagnostic tool for CRC
ABSTRACT
There are hoarding documents for the biological importance of cyclooxygenase-2 [COX-2] in pancreatic carcinogenesis. We aimed to thoroughly investigate the DNA sequence variations of whole COX-2 exons in a large case- control study of pancreatic cancer by direct sequencing. The entire exonic regions of COX-2 including 10 exons were sequenced in the germline DNA of 96 patients with pancreatic cancer. Selected variants within exons six to seven [E6E7] amplicon from the test panel were genotyped in 96 controls. The COX-2 gene was demonstrated to be genetically conserved. Four missense mutations were found in three cases. However the common variant c.724-10_724-7deIATTT [rs20123141 1] that is located in intron 6, showed significant difference between cases and controls [21 [21.9%] vs 11 [%11.5], p=0.05]. This study determined that COX-2 has a conservative sequence, which is required for its enzymatic activity and supports the important role of this enzyme's expression in pancreatic cancer rather than any changes in its activity. The effect of intronic variant rs201231411 on COX-2 expression could be analyzed in future studies
ABSTRACT
Colorectal cancer is one of the most commonly diagnosed cancers and cancer- related death worldwide. Identification of new specific biomarkers could be helpful to detection of this malignancy. Altered plasma microRNA expression has been identified in many cancers, including colorectal cancer. The main objective of this study was to identify the circulating microRNAs with the most expression changes in colorectal cancer patients compared with neoplasm free healthy individuals. MicroRNA expression profiling was performed on plasma samples of 37 colorectal cancer patients and 8 normal subjects using microRNA microarray. Quantitative real-time reverse transcription polymerase chain reaction was used to validate the two selected altered microR NAs. Plasma samples from 61 colorectal cancer patients and 24 normal subjects were used in our validation study. In profiling study we found a panel of six plasma microRNAs with significant downregulation. MicroRNA-142-3p and microRNA-26a-5p were selected and validated by polymerase chain reaction. Our results demonstrated that expression levels of plasma microRNA-142-3p and microRNA-26a-5p were significantly downregulated in patients with colorectal cancer when compared to control group. Our findings suggest that downregulation of plasma microRNA-142-3p and microRNA-26a-5p might serve as novel noninvasive biomarkers in the diagnosis of colorectal cancer, although more studies are needed to highlight the theoretical strengths