In an in vivo study, activity started to accumulate in tumor regions at 1–2 h after injection of 125I-hFab-Met-1, it was highly accumulated at 5–8 h p.i. and persisted for at least 24 h in SK-LMS-1/HGF bearing mice models, with a mean tumor activity of about 6% of the estimated activity administrated. The gene discussed is GZMM; the disease is neoplasm.