PRPS1 and neoplasm: HE staining and IHC staining of lung tissue sections showed that BALB/c nude mice carrying A875 melanoma cells with PRPS1 overexpression had significantly increased formation of lung-specific metastases, and the expression level of PRPS1 was positively correlated with the number of tumor foci compared with BALB/c nude mice bearing control cells (Figure 6E).