The glioma cell edge – winning by engulfing the enemy?

Abstract

Malignant glioma and glioblastoma multiforme form the largest group of highly malignant brain tumours, for which there is yet no definitive cure. Different approaches to treatment have been tried, in vain or with minimal benefit for the patient. In addition to surgery, radiation and chemotherapy, immunotherapy aiming at evoking an inflammatory reaction against the tumour itself has been tried. Immunotherapy has shown good results in an experimental mouse model, but no convincing efficacy/success in patients. Why are the gliomas always winning, how do they take the lead? The following phenomena lead us to propose an hypothesis about the reason for the glioma lead: the reported findings of phagocytic activity in reactive and neoplastic astrocytes in animal models and humans; the frequently observed ingested "non-self material"/debris in glioma cells; the markedly high contents of tumour cells with phagocytic phenotype in gliomas and the signs of only limited and temporary inflammatory reactions in different immunotherapy attempts. Whether it being a true phagocytosis, an engulfing or comparable activity by the glioma cells, contributing to the tumour's self defense against e.g. antitumoural therapies, it should be beneficial to attempt hampering these self defense properties e.g. by blocking their engulfing capacity.