APC and retinoblastoma: The polyps in patients hemizygous for a defective APC (disrupting the wnt/wingless pathway) and the dysplasias preceding neoplasia both in retinoblastoma and in the lethal giant larva mutant in Drosophila that eventually result in neuroblastomas are tissue organization alterations in which the underlying cause may be altered morphogen/morphostat gradients [1].