Morphological assessment of the vascular microenvironment of squamous cell carcinomas of lung

Abstract

Introduction. Non-small cell lung cancer (NSCLC), including squamous cell carcinoma, accounts for 80% of all lung cancers. Anti-angiogenic drugs are currently available for NSCLC treatment. However, there are no predictive biomarkers for selecting patients who could benefit from this therapy. The aim of the study was to assess the correlation between the density of the tumor vascular microenvironment and the tumor size, as well as between the density of tumor lymphatic vessels and the presence or absence of metastases in the ipsilateral peribronchial lymph nodes. Materials and methods. Patients with a morphologically verified diagnosis of squamous cell lung carcinoma were divided into 2 groups depending on the stage of cancer: group 1 (stage I, n=15) and group 2 (stage II, n=15). We performed a morphometric study of histological slides stained with hematoxylin and eosin and antibodies to CD34 and Podoplanin (specific and sensitive markers to blood and lymphatic vessels, re-spectively) with immunohistochemical methods. Vascular density was assessed according to the Chalkley method. We quantitatively evaluated the density of blood vessels in absolute numbers on a 0.73-mm² area with a magnification of ×200 (three fields of view were evaluated with subsequent calculation of the mean blood vessels density). Results. The median of vascular density of the microvasculature was 9.67 (8.67; 10.33) and 10.33 (9.67; 11.67) in the intratumoral zone in group 1 and group 2, respectively. In the peritumoral zone, it was 12 (11.33; 12.67) for group 1 and 16.33 (15.67; 19.67) for group 2. The median density of lymphatic vessels in group 1 and group 2 in the intratumoral zone amounted to 1.5 (1; 2) and 2 (1.67; 3.75), respectively; whereas in the peritumoral zone, this parameter was 2 (1.92; 2.75) and 3.33 (2.67; 4) for groups 1 and 2, respectively. We found a correlation between tumor size and vascular density of the microvasculature in the peritumoral zone (p<0.05) and between the density of lymphatic vessels in the peritumoral zone and the presence of metastases in the peribronchial lymph nodes (p<0.05). Conclusion. Features of the vascular microenvironment of the tumor contribute to the progression of squa-mous cell carcinoma of the lung. Keywords: squamous cell lung cancer, tumor vascular microenvironment, tumor vascular density