AB062. Investigating miR-21 as a non-invasive prognostic biomarker in glioma patients.

Abstract

Glioma prognosis remains a challenge due to its high recurrence and resistance to treatment. Diagnosis and follow-up in resource-constrained regions often lead to significant patient attrition. Serum microRNAs (miRNAs) are seen to be aberrantly expressed in malignancies can be found in tumor tissues and peripheral samples. This offers a pathway for non-invasive liquid biopsies. miR-21 is an established biomarker for glioma prognosis, which needs to be validated in our population. We collected 89 intraoperative tumor tissue samples, and 42 pre- and post-operative serum samples from glioma patients, ten control tissues, eight healthy serum samples and analysed for miR-21 expression through quantitative polymerase chain reaction (qPCR) analysis. Correlational analysis with molecular markers isocitrate dehydrogenase (IDH), Ki-67, ATRX, p53, and survival curves through the Kaplan-Meier method were calculated in high and low miR-21 expression groups. The hazard ratio was quantitatively determined using Cox regression analysis, considering both univariate associations and multivariate correlations with clinical parameters. miR-21 expression in tissue was significantly upregulated with increase of glioma grades (P<0.001) and in patients above 50 years (P=0.003) age group. Whereas no gender bias was seen in its expression pattern. Its expression did not show any correlation with tumor volume (r=0.22, P=0.08). A similar expression pattern of miR-21 was observed in serum samples of glioma. IDH-wildtype (P=2.06e-03) and high Ki-67 (P=2.50e-03) patient group showed significant upregulation of miR-21 expression compared to IDH-mutant and low Ki-67 group. Patients with low miR-21 expression had significantly longer overall survival (OS) than patients with high miR-21 expression (P =0.006). Similarly, quantitative hazard analysis indicates that patients in the high expression group have 2.77 times higher risk of mortality [95% confidence interval (CI): 0.19-0.92], in comparison to patients in the low expression group (P=0.008). Our findings validate the utility of miR-21 as a prognostic serum biomarker to help diagnose and assess treatment response in advancing glioma grades, within our population.