EGFR and glioblastoma: Also, the absence of EGFRvIII in an additional tumor sample from the same patient, and expressing significantly lower levels of EGFR, corroborates reports suggesting that EGFR over-expression is linked to the presence of EGFRvIII. The apparent mosaic pattern of EGFRvIII expression in the EGFRvIII-positive patient also confirms the heterogeneity of OSCC similar to malignant glioblastomas, where the proportion of EGFRvIII-expressing cells has been shown to range from 37% to 86% in EGFRvIII-positive tumor samples [32].