Under diverse stimuli (e.g., infections, tumours, etc.), the eosinophils are able to release different substances, such as, eosinophil cationic protein (ECP), major basic protein (MBP), eosinophil peroxidise (EPO), eosinophil-derived neurotoxin (EDN), IL-1, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, IL-18, interferon (INF)-γ, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-α, TGF-β, chemokines (RANTES, endotaxin-1), platelet-activating factor (PAF), leukotriene C4 (LTC4), neuromediators, and indoleamine 2,3-dioxygenase (IDO) [4, 5]. This evidence concerns the gene RNASE2 and neoplasm.