Collectively, the findings indicate that cellular crosstalk between GBM and macrophage through sICAM‐1‐WNT3A oncogenic route is involved in the mesenchymal shift of GBM cells after radiation, and suggest that radiotherapy combined with sICAM‐1 targeted inhibition would improve the clinical outcome of GBM patients. The gene discussed is WNT3A; the disease is glioblastoma.