Fluorophores conjugated to the integrin-targeting tripeptide RGD (arginine-glycine aspartic acid) (IRDye 800CW-RGD) or the protein tyrosine phosphatase mu-targeting peptide SBK2 (Cy5-SBK2) have shown a high fluorescence intensity ratio in glioblastoma cells compared to normal cells, but have not yet been demonstrated in vitro [49, 50]. The gene discussed is PTPRM; the disease is glioblastoma.