Other molecules that have been detected in the aqueous humor and could dampen anti-tumor immune responses include α-melanocyte-stimulating hormone (α-MSH), calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP), and somatostatin, by which delayed-type hypersensitivity reactions are suppressed and Treg cell activity is induced (13, 31, 32). This evidence concerns the gene VIP and neoplasm.