To elucidate the role of EGFR overexpression over its constitutively active form EGFRvIII, we screened LN229EGFR GBM cells (both overexpressing the EGFR protein, without expressing the constitutively active version EGFRvIII) for their 5-ALA-induced fluorescence. Here, EGFR is linked to glioblastoma.