MALAT1 expression in oral squamous cell carcinoma - A Systematic review and meta-analysis

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Background: MALAT1 (Metastasis-Associated Lung Adenocarcinoma Transcript 1) is a long non-coding RNA that helps in disease prognosis. Objective: The aim of the study is to provide updated evidence on the expression rate of MALAT1 in oral squamous cell carcinoma (OSS) compared to normal cells and its other histopathological gradings, like well-differentiated, moderately differentiated, and poorly differentiated OSCC. Materials and Methods: The review adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered in PROSPERO with the registration number CRD42024598836. A thorough search of databases was conducted from January 2000 to April 2024 to identify studies reporting the MALAT1 expression in OSCC cells compared to normal cells and its histological gradings of OSCC. Quality assessment was performed using the Newcastle Ottawa scale (NOS) for included studies. The standardized mean difference (SMD) was used for continuous outcomes, while odds ratio (OR) and risk ratio (RR) were applied for categorical outcomes, depending on the data reported. A random-effects model was used for all analyses, with statistical significance set at P < 0.05. Results: Seven studies qualified for inclusion, with four undergoing meta-analysis. Quality assessment indicated a moderate to low risk of bias. The meta-analysis revealed increased MALAT1 expression in OSCC cells (SMD = 3.90, 1.20-6.61) compared to normal tissue. Among OSCC grades, MALAT1 expression was higher in moderately differentiated OSCC than in well-differentiated (SMD = 5.50, –15.08–26.08), lower in moderately differentiated than in poorly differentiated (SMD = 10.50, –27.16–6.61), and lower in well-differentiated than in poorly differentiated OSCC (SMD = 1.50, –2.48–0.52). No publication bias was detected in the funnel plot. Conclusion: MALAT1 is a therapeutic factor in OSCC; its increased expression is related to OSCC growth and could help control metastasis, with overall good clinical relevance, making it a promising prognostic marker for OSCC.