VIPR1 and neoplasm: One case report shows that a patient with WDHA syndrome was successfully treated with octreotide, a somatostatin analog, and octreotide-based radionuclide scanning localized the pancreatic tumor, which was VIP and VPAC1 positive by immunohistochemistry63, suggesting that hypersecretion of VIP from a VIPoma affects tumor growth and that VIP release is modified via VPAC1 activation with positive or negative feedback.