These data show conclusively that glioma tumor cells even in low-grade tumor biopsies expressing EGFR can be visualized at both macroscopic and microscopic magnifications by specifically staining with monoclonal antibodies against EGFR and/or EGF, and in some cases to monoclonal antibodies against PDGFR, coupled to quantum dots. The gene discussed is EGFR; the disease is glioma.