EGFR and glioblastoma: Changes in E-, N- and VE-cadherins, VCAM-1, and EGFR were analyzed by immunohistochemical reactions, Western blot, and ddPCR methods in U-87 MG cells and GBM spheroids consisting of U-87 MG glioblastoma cells, HMEC-1 endothelial cells and macrophages;