Tumor Immune Microenvironment

This prospective observational study aims to evaluate whether immune profiles of T-cell subsets in bronchoalveolar lavage fluid can complement tumor PD-L1 expression, assessed by immunohistochemistry in tumor tissue specimens, in predicting clinical outcomes in patients with advanced lung cancer. Although tumor PD-L1 expression measured on tissue biopsies is widely used to guide immunotherapy decisions, its predictive value is limited by spatial heterogeneity and sampling variability. By analyzing activated, exhausted, and regulatory T-cell populations in bronchoalveolar lavage fluid and examining their association with tissue-based tumor PD-L1 expression, this study seeks to determine whether combining local immune biomarkers with PD-L1 expression improves the prediction of treatment response and survival in patients receiving standard-of-care systemic therapy.