Sampedro-Núñez in human primary and metastatic gastro-entero-pancreatic neuroendocrine tumors studied the presence and potential functional roles of truncated variants of somatostatin receptors, and their relationships with the angiogenic system Ang/Tie-2 and VEGF by Real Time-PCR, immunofluorescence and immunohistochemistry [124]. Here, VEGFA is linked to pancreatic neuroendocrine tumor.