It has also been revealed that EGFR and HER-2 can potentiate tumour cell adhesion to endothelial cells, by enhancing the synthesis of hypoxia-inducible factor (HIF)-1α, and/or carbonic anhydrase-9 (Giatromanolaki et al, 2001; Laughner et al, 2001) through a PI3 kinase-dependent pathway (Bagheri-Yarmand et al, 2000). This evidence concerns the gene CA9 and neoplasm.