Gao and colleagues described cRGD-QCas an MMP-2 activatable probe featuring a Cy5 dye, a QSY21 quencher,and a tumor targeting cyclic RGD covalently bound through a 125I labeled peptide substrate.88 Upon cleavageby active MMP2, cRGD-QC emitted a strong NIR signal and the cRGD tumor-targetingmoiety enhanced probe in vivo accumulation in tumors,which was detected by NIR fluorescence and SPECT imaging. The gene discussed is MMP2; the disease is neoplasm.