Association of survival with clinical characteristics and CD68/CD206 expression in stage IIIA squamous cell lung carcinoma.

e20027 Background: Stage IIIA squamous cell lung carcinoma (SqCLC) has a poor prognosis, with 5-year survival rarely exceeding 30-35% even after radical treatment. The tumor microenvironment, particularly tumor-associated macrophages (TAMs), plays a key role in non-small cell lung cancer biology. This study aimed to evaluate the association between overall survival (OS) in stage IIIA SqCLC and clinical factors along with the expression of CD68 (pan-macrophage marker) and CD206 (M2-like macrophage marker) in tumor stroma and parenchyma. Methods: The study included 31 patients with stage IIIA SqCLC. Based on the median OS (42 months), patients were divided into short-survivors (OS < 42 months, n=20) and long-survivors (OS ≥ 42 months, n=11). Immunohistochemical staining was performed for CD68 (KP-1, Cell Marque) and CD206 (Orb94710, Biorbyt). The Mann-Whitney U test, Pearson's χ² test, and Spearman's correlation were used for statistical analysis. Results: High stromal CD68 expression was associated with better OS. The median stromal CD68 level was 1.4-fold higher in long-survivors (20 [IQR: 18.5-28.5]) compared to short-survivors (p=0.002). No significant survival differences were found for parenchymal CD68 or tumor CD206 expression. Adverse prognostic clinical factors included pneumonectomy (2.9 times more frequent in short-survivors, p=0.039) and the presence of comorbidities (2.8 times more frequent in short-survivors, p=0.001). Tumor size, nodal involvement, smoking status, and treatment regimens showed no significant differences. A significant negative correlation between stromal CD68 and parenchymal CD206 was found in long-survivors (ρ=-0.74, p<0.05), which was absent in the short-survivor group. Conclusions: The integration of clinical factors (pneumonectomy, comorbidities) with immunohistochemical markers, specifically high stromal CD68 expression and its inverse correlation with parenchymal CD206, may improve risk stratification and prognosis in patients with stage IIIA squamous cell lung carcinoma.