الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The role of miRNAs in post-transcriptional events and cell metabolism is well established. MiRNAs are small, stable, quantifiable non-coding RNAs. They are involved in the regulation of gene expression and play a critical role in many biological processes. MiRNAs regulate mRNA stability by targeting mRNA for degradation or translational repression. They also regulate protein synthesis by modulating the expression of gene products. Several preliminary studies have shown that miRNAs are differentially expressed in CLD and HCC, but a question remains whether miRNAs can serve as non-invasive biomarkers that can be used to assess the severity of the disease and improve patient survival and morbidity in cirrhosis.
Further studies are needed to investigate the role of miRNAs in cirrhosis and to determine which miRNAs can be used as biomarkers to assess the severity of the disease and improve prognosis. The use of miRNAs as biomarkers is currently being studied as a way to predict the outcome of patients with cirrhosis and to determine their prognosis and response to treatment. A focus should be placed on validating the clinical effectiveness of miRNA-based biomarkers in the future. The new information could contribute to the development of personalized medicine for cirrhosis. New therapeutic interventions can also be developed with this method. Finally, miRNA-based biomarkers may be able to serve as early diagnostic tools for cirrhosis.
Therefore, this thesis demonstrated the different expression of different miRNAs as a tool to diagnose the HCC in early stage, further, to discriminate between the different stages of liver disease (i.e.: Fibrosis, Cirrhosis and HCC stages).
The significant results of the current study were summarized in the following points:
1. Significant differences in the expression of has-miR-21, has-miR-143, has-miR-519d, has-miR-221, has-miR-425-3p, and has-miR-218 across the study groups, qRT-PCR validation confirmed the presence of these miRNAs or significant differences in their expression; the miR-21 and miRNA-219- 5p revealed a trend towards increased expression in cirrhotic patients compared with mild disease.
2. MiR-21 and miRNA-143 expression in serum were both considerably higher in HCC patients compared to F2-F4 patients, p=0.053 and p= 0.054, respectively), whereas miR-221 expression was significantly downregulated in HCC patients.
3. The expression of miR-425-3p and miR-218 was, however, also considerably decreased in HCC than in the other groups (p<0.05). Curiously, miR-21 and miR-218 were discovered to be highly expressed in cirrhosis.
4. The qRT-PCR confirmed the results of ROC analysis. Using miR-21 and miR-218 to distinguish cirrhosis from mild disease resulted in AUCs of 0.845 (p=0.005) and 0.792 (p=0.041), respectively.
5. High accuracy of miR-21 in diagnosing early HCC.
6. Combining both AFP and miRNA-21 resulted in a marginally improved AUC of 0.845 (95% CI 0.645 to 0.957). In the detection of early HCC, combining AFP and miRNA-143 to a diagnostic panel results in an improved diagnostic performance with an AUC of 0.79 (95% 0.0698 to 0.585) with significant p value 0.0127.
7. Next generation sequences revealed that the cirrhotic samples revealed 14 documented genetic variations, 9 of which were shared by control samples with a frequency ratio of more than or equal to 50%. These samples revealed the following 5 genetic variations, one of which was identified in one control sample (frequency ratio 16.5 %).
8. MiR-21 transfected IHH cells showed a trend towards increased PTEN expression (p=0.02) at 24h post-transfection.
9. Analysis of miR-21 qRT-PCR data showed a significant decrease of mTOR expression at 24h post-transfection (p=0.01) and significantly increased expression of IL23p40 at 48h post transfection, when compared to controls at the same time point.
10. hsa-miR-21 and hsa-miR-218 interact more with PTEN than mTOR, promoting cancer proliferation and inhibiting apoptosis. Consequently, the increased binding of hsa-miR-218 to EGFR over PTEN and Met-1 to mTOR has implications for cancer biology, suggesting that hsa-miR-21 and hsa-miR-218 may be more likely to promote cancer proliferation and inhibit apoptosis.
11. EGFR and Met1 exhibit higher ACEs than hsa-miR-218 to PTEN and mTOR, in contrast to these findings
To conclude, despite not yet having adequate diagnostic precision as a biomarker for HCC, miRNA-21 performed equally well with the widely used tumor marker AFP in this patient population. Moreover, the present study detected 6 candidates for differentially-expressed miRNAs, but only validated substantial differential expression in miRNA-21 because of technical limitations. This is due to the fact that the expression of miRNA-21 was found to be significantly higher in early HCC samples compared to the non-cancerous samples. Additionally, the findings of the study suggest that miRNA-21 could potentially be used as a diagnostic biomarker for early detection of HCC, which would enable early intervention and better treatment outcomes.
Several investigations with more patient samples are planned to further study these early candidates and maybe validate a new miRNA that is unique to early HCC and can be used as a diagnostic biomarker for early intervention in this fatal disease.