An example of an antigen found to be overexpressed in RCC is carbonic anhydrase IX (CA9), which is the target for the monoclonal antibody (mAb) G250 (Pastorek et al, 1994; Uemura et al, 1999; Grabmaier et al, 2000; Li et al, 2001; Bui et al, 2003). Here, CA9 is linked to renal cell carcinoma.