Microenvironment influence on the development of epithelial-mesenchymal transformation in lung cancer

Relevance. Epithelial-mesenchymal transformation (EMT) largely determines the biological behavior and prognosis of cancers of various localizations. It is known that the determining role in the control and implementation of the transition of the epithelial phenotype to the mesenchymal belongs to the microenvironment. At the same time, the histochemical and microscopic characteristics of stromal elements remain unclear; therefore, the aim of our study was to establish the morphological features of the stroma that affect the development of EMT in lung cancer. Materials and Methods. We studied 32 cases of lung cancer with hematoxylin and eosin staining of sections, Alcian blue at pH 1.0 and 2.5, PAS reaction, as well as immunohistochemical studies with monoclonal antibodies to HMW, AE 1 / AE 3, cytokeratin 18, c-erb B 2, vimentin E-cadherin, alpha-smooth muscle actin, GFAP and chromogranin A, Ki-67. In 16 cases, there was widespread epithelial-mesenchymal transformation (EMT), in 14 cases - focal and in 2 cases EMT was absent. In half of the cases of widespread EMT, it was complete; among the cases of focal EMT, it was not complete. The transition from the epithelial to the mesenchymal phenotype was facilitated by the activation of the stroma, namely, the presence of myofibroblasts and alcianophilia of the extracellular matrix, inflammatory cell infiltration, expression of the epidermal growth factor receptor (c-erb B 2) in stromal cells, proliferation and neurogenic differentiation of stromal cells of stromal cells. Results and Discussion. The activated stroma correlates with the frequency of EMT. Thus, large areas of activated stroma with the presence of myofibroblasts and alcianophilia of the extracellular matrix are more common in cases of widespread EMT (14 out of 16-87.5 %) than in cases of focal EMT (4 out of 14-28.6 %). The differences are statistically significant, p < 0.01. Inflammatory cell infiltration, which is the source of a signal for transformation, expression of the epidermal growth factor receptor (c-erb B 2) in stromal cells, proliferation, and neurogenic differentiation of stromal cells also correlated with the frequency of EMT. In all cases, the differences are statistically significant, p<0.01. Conclusions. The data obtained indicate the undoubted influence of signals from the activated stroma on the development of epithelial-mesenchymal transformation of tumor cells.