Immunohistochemical studies of various tumor tissues revealed that CA IX is co-expressed with diverse signaling molecules, including EGFR, MUC-1, cErb22, CD44, VEGF, etc. and at least in some cases this may suggest cross-talk between the pathways related to these molecules (Giatromanolaki et al., 2001; Bartosova et al., 2002; Swinson et al., 2004; Skrzypski et al., 2008). The gene discussed is CA9; the disease is neoplasm.