Electron microscopy of red fluorescent protein (RFP)-labeled glioblastoma cells. Quantification of neuron-to-glioma synaptic structures as a percentage of all visualized glioma cell processes (left) and image of neuron-to-glioma process in a high-neural glioblastoma xenograft (right). Asterix denotes immunogold particle labeling of RFP. Postsynaptic density in RFP + tumor cell (green), synaptic cleft and vesicles in presynaptic neuron (red) identify synapses. P < 0.01, two-tailed Student’s t -test. Scale bar, 200 nm. Data are mean ± s.e.m. n = 3 biological replicates.
