Finally, to assess the role of stromal CA IX in promoting in vivo tumor growth, we co-injected PC3 cells and CAFs (1:5 ratio) in the lateral flanks of SCID-bg/bg mice and we observed that fibroblasts knock-down for CA IX are less able to sustain tumor mass growth compared to control experiment with non-silenced fibroblasts (Figure 9). The gene discussed is CA9; the disease is neoplasm.