Pre and Postoperative Serum miR-21 Expression Levels in Oral Cancer and it's Association with Clinical and Histological Parameters: An Observational Study.

Introduction: The patterns of microRNA (miRNA) expression have opened up new avenues in the search for prognostic biomarkers and potential therapeutic targets for various tumours. In oral carcinogenesis research, analysing microRNAs expressed in Oral Squamous Cell Carcinoma (OSCC) unveils a complex network of interest. miR-21 is known to be overexpressed in numerous solid tumours and is linked to the progression of malignancies in hepatocellular carcinomas, breast cancer, and colon carcinomas. Aim: To determine the impact of surgical excision on serum miR-21 expression levels in OSCC cases and to establish correlations with clinicopathological parameters. Materials and Methods: The study was an exploratory prospective observational study conducted with proper institutional ethical approval at the Cancer Research Institute (CRI), Himalayan Institute of Medical Sciences (HIMS), Jolly Grant, Dehradun, Uttarakhand, India. Fifty-six histologically confirmed OSCC cases were enrolled along with 25 healthy subjects as controls from May 2021 to June 2023. The relative fold expression change was calculated using the Livak method (2-ΔΔct). Data analysis was performed using software such as Statistical Package for Social Sciences (SPSS) version 20.0 and MS Excel. Non parametric statistical tests such as Wilcoxon signed-rank test, Mann-Whitney test, and Kruskal-Wallis test were utilised. Results: Out of 56 sample included, 28 exhibited high expression of miR-21 (p-value<0.001), while 27 cases showed downregulation postsurgery (p-value<0.001), with one sample showing the same level of expression. In cases where the time difference between pre and postsurgery samples was over 25 days, no significant change was observed (p-value=0.06), and similarly, in cases with a time difference below 25 days, no significant difference was noted (p-value=0.14). A significant negative correlation was found between presurgery serum Albumin to Globulin ratio (A:G ratio) and miR-21 expression (p-value <0.05), while no other parameters showed a significant correlation with miR-21. Conclusion: miR-21 expression decreased significantly in some OSCC cases; however, in the majority of cases, it increased postsurgery. A significant correlation was observed between miR-21 expression and the serum A:G ratio. [ABSTRACT FROM AUTHOR]