FIG. 7.

NK2 enhances metastatic efficiency, but not growth, of high-Met-expressing melanoma cells. The figure shows results of analysis of liver metastasis of melanoma cells in genetically modified host mice. One million 37-32 melanoma cells were injected intravenously into the tail vein of wild-type (WT), NK2 transgenic, NK1 transgenic, and HGF/SF transgenic mice. (A and B) After 3 weeks, livers were examined grossly (A) and histopathologically (B) for the presence of metastatic tumors. Melanomas were immunohistochemically visualized (brown staining) using an anti-mouse TRP1 antibody. (C) Liver preparations from the genetically modified host mice were used to quantify both mean numbers of 37-32 melanoma cell metastases (white bars) and mean tumor sizes (black bars). Error bars indicate standard errors of the means. There was no statistically significant difference in the numbers of metastases per liver in the three transgenic lines. For mean tumor size, P value was <0.001 for NK2 versus either NK1 or HGF/SF; P value was 0.2 for NK1 versus HGF/SF.