<![CDATA[Background: Lung cancer remains the leading cause of cancer-related mortality worldwide and is often diagnosed at an advanced stage. TGF-β1 plays a pivotal role in carcinogenesis and may serve as a diagnostic biomarker. BALF represents a relevant medium for assessing biomarkers that reflect the tumor microenvironment. This study aimed to evaluate TGF-β1 levels in BALF and determine its diagnostic performance and optimal cut-off value for lung cancer. Methods: This cross-sectional analytical study was conducted at Dr. Zainoel Abidin General Hospital, Banda Aceh, from April to June 2025, involving 64 patients (34 lung cancer patients, 9 suspected lung cancer patients, and 21 non-cancer patients). BALF samples were obtained via bronchoscopy, and TGF-β1 levels were measured using ELISA. Statistical analyses included the Mann-Whitney U test and ROC curve analysis. Results: Median TGF-β1 levels were 66.24 pg/mL in the non-cancer group, 136.93 pg/mL in the suspected lung cancer group, and 200.25 pg/mL in the lung cancer group. The combined suspected/lung cancer group showed significantly higher levels than the non-cancer group (P=0.025). ROC analysis yielded an area under the curve (AUC) of 0.674 (95% CI=0.529-0.819; P=0.025). The optimal cut-off value was 105.63 pg/mL, with a sensitivity of 67.44%, specificity of 61.90%, positive predictive value of 78.38%, and negative predictive value of 48.15%. Conclusion: TGF-β1 levels in BALF demonstrate potential as a diagnostic biomarker for lung cancer with moderate performance. It may serve as a supportive “rule-in” test to strengthen clinical suspicion but is insufficient as a stand-alone diagnostic tool. Combining TGF-β1 with other biomarkers in a multiparametric diagnostic panel is recommended to improve diagnostic accuracy.]]>
