EGFR and glioblastoma: While full-length E-cadherin is low or absent in brain tumor cells, expression of variant E-cadherin from circRNAs was high, was secreted by glioma stem cells, and acted as an autocrine ligand to amplify EGFR signaling independent of EGF, resulting in sustained glioblastoma stemness (Gao et al., 2021).