When HGF-low and HGF-high lung cancer cells were inoculated in human HGF knock-in mice—in which the endogenous mouse HGF gene was replaced by the human HGF gene and radiolabeled HiP-8 was administered—the efficient accumulation of HiP-8 occurred in HGF-high cancer at a higher level than that in HGF-low cancer (Figure 6) [20]. This evidence concerns the gene HGF and lung cancer.