Interestingly, mice lacking PKD1 die in utero, whilst mice lacking PKD2 are phenotypically normal and viable, indicating that PKD2 is not strictly required for the functioning of normal cells.30 These combined studies indicate that PKD2 is a crucial mediator of the angiogenic response being both needed in the tumor endothelial cell (for proliferation, migration and tube formation) as well as in the tumor cell (for expression and secretion of angiogenic factors). The gene discussed is PKD2; the disease is neoplasm.