Mesenchymal/radioresistant traits in granular astrocytomas: Evidence from a combined clinical and molecular approach

AIMS: Granular cell astrocytomas (GCAs) are morphologically characterized by a prominent component of granular PAS-positive cells and show an increased aggressiveness compared to "ordinary" astrocytomas. Here, we studied in a small series of three GCAs the expression of mesenchymal/radioresistance-associated biomarkers (such as YKL-40, c-Met and Cav1), which could contribute to the poor outcome of this glioma subgroup. METHODS AND RESULTS: Our results show that GCAs, according to the new molecular glioma classifications, consistently display a prognostically negative molecular trait (IDH1wt-ATRX noloss-1p/19q nocodeletion). Furthermore, GCAs significantly differ from a control series of 33 "conventional" astrocytomas, because of a diffuse and strong immunohistochemical coexpression of YKL-40, c-Met and Cav1. CONCLUSIONS: Our findings show that specific morphological traits, such as a granular cell component, could represent useful features in guiding search for prognostic and predictive biomarkers, eventually amenable to targeted therapies (i.e. Met-inhibitors aimed at reducing radio-resistance).