In conclusion, we found that EGFRvIII expression is closely related to GBM and can affect the gene expression profile of tumor tissue in GBM patients; GBM patients with EGFRvIII (+) have low sensitivity to TMZ; and EGFRvIII regulates the expression of ALDH1A3 by activating NF-κB, thus promoting the proneural–mesenchymal transition of GBM and reducing its sensitivity to TMZ. The gene discussed is ALDH1A3; the disease is neoplasm.