Analysis of the respective Raman spectra (averaged over areas of highest intensities shown in Figure 4C) shows that different levels of EGFR expression are also represented at various intensities of the Raman spectra: higher intensity for the EGFR high-expressing brain tumor (red spectrum) and lower intensity for the EGFR low-expressing brain tumor (blue spectrum) (Figure 4E). The gene discussed is EGFR; the disease is brain neoplasm.