Cell Transformation, Neoplastic/genetics; Colorectal Neoplasms/genetics; Mutation; Receptor, Cholecystokinin B/genetics; Stomach Neoplasms/genetics; Animals; Cell Movement/genetics; Cell Shape/genetics; Cell Transformation, Neoplastic/metabolism; Cells, Cultured; Coculture Techniques; Colorectal Neoplasms/metabolism; Colorectal Neoplasms/pathology; DNA Mutational Analysis; Endothelial Cells/metabolism; Endothelial Cells/physiology; HEK293 Cells; Humans; Immunoblotting; Mice; Microscopy, Fluorescence; NIH 3T3 Cells; Neovascularization, Pathologic/genetics; Neovascularization, Pathologic/metabolism; Neovascularization, Pathologic/physiopathology; Neovascularization, Physiologic/genetics; Neovascularization, Physiologic/physiology; Phenotype; RNA Interference; Receptor, Cholecystokinin B/metabolism; Receptor, Cholecystokinin B/physiology; Stomach Neoplasms/metabolism; Stomach Neoplasms/pathology; Transfection; Vascular Endothelial Growth Factor A/metabolism