# A novel approach in the identification of microRNAs in malignant pleural effusion for lung cancer diagnosis

## TL;DR

This paper reviews current research on microRNAs in malignant pleural effusion as potential biomarkers for diagnosing lung cancer.

## Contribution

The study provides a narrative review highlighting the potential of microRNAs in pleural effusion as novel biomarkers for lung cancer.

## Key findings

- 17 studies identified 106 microRNAs with significant overexpression and downexpression in lung cancer patients.
- Eight studies showed 17 microRNAs with high diagnostic accuracy for lung cancer hallmarks.
- MicroRNAs regulate complex mechanisms like cell growth, migration, and apoptosis in cancer.

## Abstract

Pleural effusion, an atypical accumulation of fluid in the pleural space, has been identified as a potential indicator of several diseases, including lung cancer. The presence of biomarkers in malignant pleural effusion has been a subject of investigation; however, the expression of microRNAs has received limited attention. The objective of this study is to present a narrative review of the current scientific literature regarding the presence of microRNAs in malignant pleural effusion and their association as new biomarkers in the diagnosis of lung cancer.

A comprehensive search was conducted using the databases: PubMed, ScienceDirect, and EBSCO to identify all original scientific articles published through 30 April 2025. The following terms were utilized in the search: “MicroRNA AND pleural effusion AND lung cancer”, “microRNA AND pleural effusion AND lung adenocarcinoma”, “microRNA AND pleural effusion AND lung squamous cell carcinoma”, “miRNA AND pleural effusion”, miRNA AND pleural effusion AND lung cancer”, “miRNA AND pleural effusion AND lung adenocarcinoma”, “miRNA AND pleural effusion AND lung squamous cell carcinoma”.

A total of 17 studies were identified that distinguished between 106 microRNAs. These studies demonstrated the most significant overexpression and downexpression in lung cancer patients compared to patients without malignancy. However, eight of these studies distinguished between 17 microRNAs expressions and exhibited elevated area under the curve values, sensitivity, and specificity for the involvement in several hallmarks of lung cancer.

The regulatory mechanisms governing microRNAs in malignant pleural effusion are intricate and involve multiple genes that play pivotal roles in several cancer mechanisms. These mechanisms encompass but are not limited to, processes such as cell growth, migration, drug resistance, proliferation, apoptosis, invasion, angiogenesis, and apoptosis.