Endothelial cells and angiogenesis intensity in lung cancer

We focused our studies on single endothelial cells (ECs) scattered in extracellular matrix in lung cancer tumors. Neovascularization was evaluated in 100 tumors obtained from patients operated for lung cancer, in relation to histological type, tumor differentiation and clinical stage of the disease. Angiogenic objects (single endothelial cells and microvessels) were identified by immunohistochemistry using monoclonal antibodies against von Willebrand factor. The count of angiogenic objects per 1 mm2 in each section was determined in a "hot spot" located at the margin of the tumor. We used an arbitrary scale of angiogenesis intensity: 1 - 0-200, 2 - 201-400, 3 - >400 angiogenic objects/mm2. A majority (57%) of the examined cases belonged to the group 2. The angiogenesis intensity measured by the single EC numbers/mm2 correlates with the histological type and the differentiation of the tumors. There was no such a correlation when the angiogenesis intensity was measured by counting total angiogenic objects (microvessels + EC) number/mm2. Single EC number/mm2 in different histological types of cancer were as follows: 162+/-121 in squamous cell (SqCC), 194+/-71 in adenocarcinoma (AdC), 225+/-145 in large cell (LCC), 264+/-52 in small cell (SCC), 279+/-173 in combined cancer. The differences between the EC counts in the different histological types of lung cancers were statistically significant in the following pairs: SqCC vs SCC (p=0.0233) and AdC vs SCC (p=0.0409). The correlation between EC count in the "hot spot" and the grade of tumor differentiation was statistically significant for G1 vs G4 (p=0.0007) and G1 vs G2 (p=0.0411). Our results suggest that higher numbers of EC/mm2 may confirm rapid development of angioneogenesis. These relations should be examined in larger series of cases.