Abstract
<title>Abstract</title> <p>Background Patients with lung adenocarcinoma face challenges such as drug resistance, low detection rates of positive markers, and difficulties in diagnosing and treating those who cannot tolerate surgical biopsies due to pleural effusion. Therefore, identifying new molecular biomarkers with potential therapeutic targets is urgently needed. Methods This study used differentially expressed genes between LUAD tumor tissues and adjacent normal tissues from the Gepia2 and TCGA databases to identify AU-rich element RNA-binding factor 1 (AUF1) as a novel biomarker for LUAD. The expression levels of AUF1, TFF-1, and NapsinA were analyzed in 120 surgically resected lung adenocarcinoma tissues and their paired adjacent normal tissues, 50 needle biopsy samples of lung adenocarcinoma and their matched normal tissues, and paraffin-embedded specimens of pleural effusions from 50 lung adenocarcinoma patients and 20 non-tumor controls. Results Immunohistochemical analysis revealed that AUF1 was significantly upregulated in LUAD tissues compared to normal control tissues in the 120 surgical specimens, and its expression correlated with tumor size, T stage, and pleural invasion. Furthermore, AUF1 expression was assessed in cell blocks derived from needle biopsies of 50 LUAD patients, pleural effusions from 50 LUAD patients, and 20 non-tumor individuals. Results showed high AUF1 expression in both needle biopsy samples and malignant pleural effusions from LUAD patients. Moreover, AUF1 expression was consistent with that of TTF-1 and NapsinA in LUAD tissues and malignant pleural effusions. Conclusion This study highlights the potential diagnostic value of AUF1 in surgical resection specimens, needle biopsy samples, and pleural effusions of LUAD patients. Our findings have significant implications for the pathological diagnosis of lung needle biopsies and malignant pleural effusions.</p>