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The liver is an organ that is particularly exposed to reactive oxygen species (ROS), which not only arise during metabolic functions but also during the biotransformation of xenobiotics. The disruption of redox balance causes oxidative stress, which affects liver function, modulates inflammatory pathways and contributes to disease. Thus, oxidative stress is implicated in acute liver injury and in the pathogenesis of prevalent infectious or metabolic chronic liver diseases such as viral hepatitis B or C, alcoholic fatty liver disease, non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Moreover, oxidative stress plays a crucial role in liver disease progression to liver fibrosis, cirrhosis and hepatocellular carcinoma (HCC). Herein, we provide an overview on the effects of oxidative stress on liver pathophysiology and the mechanisms by which oxidative stress promotes liver disease.

Introduction: MicroRNAs (miRs) are a group of endogenous, non-coding, 18-24 nucleotide length single-strand RNAs that mediate gene expression at the post-transcriptional level through mRNA degradation or translational repression. They are involved in regulating diverse cellular biological processes such as cell cycle, differentiation, and apoptosis. The deregulation of miRs affects normal biological processes, leading to malignancies, including oral squamous cell carcinoma (OSCC). This study evaluates the expression level of miR-21-5p and miR-429 genes in biopsy samples from patients with OSCC and performs a comparison with controls. Materials and Methods: In this study, tissue samples were obtained from 40 individuals (20 OSCC patients and 20 healthy controls) to determine miR-21-5p and miR-429 expression using the ΔCT method and analyzed by the Mann–Whitney test. Results: The mean age of subjects in the control and patient groups was 47.15 and 53.8 years, respectively. According to the Mann–Whitney test, significant differences were observed in miR-21-5p (p < 0.0001) and miR-429 (p = 0.0191) expression levels between the two groups (p < 0.05). Conclusions: The expression of miR-21-5p, miR-429, and combined miRNAs in the OSCC group was significantly higher compared to the control group. As a result, changes in the expression of these biomarkers in cancerous tissues could potentially be considered as a marker for the early diagnosis of OSCC.

Background and objective: Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy. Expression patterns of microRNAs (miRNAs) can direct us in identifying valuable biomarkers for the prognosis of different neoplasms. Inappropriate regulation of miRNAs during physiological procedures can result in malignancies including OSCC. The aim of the present study was to evaluate the expression of miR-486-3p, miR-561-5p, miR-548-3p, and miR-509-5p in tissue biopsy samples with and without OSCC. Materials and methods: This case-control study was conducted on 17 healthy and 17 OSCC tissue biopsy samples. The expression of miRNAs was assessed using quantitative real-time PCR (q-RT-PCR) after RNA extraction from normal and cancer tissues and cDNA synthesis. Results: The means of miRNA-486-3p, miR-561-5p, and miR-548-3p expression were significantly different between OSCC and control groups (p < 0.001), but there was no significant difference in means of miR-509-5p expression between OSCC and control groups (p = 0.179). Conclusions: The findings of this study revealed that the expression of miR-486-3p and miR-561-5p was significantly lower in cancer samples compared to normal tissue samples. On the other hand, miR-548-3p expression increased in the OSCC group compared to the control group.