MMP-2 (gelatinase, found to be correlated to numerous cancer types and to poor outcome) was also targeted by direct conjugation of Cy5.5 or rhodamine with its specific target peptide (MMP-Cy5.5 [98] or MMP2-TMR, respectively) [99], and probe accumulation was monitored during time, showing the specificity of the probe and identifying a sensitive method for the in vivo imaging of MMP-2 expression. The gene discussed is MMP2; the disease is cancer.