IL15 and neoplasm: Also, it has been well established that systemically administered IL-15 agonists – single-chain IL-15 (45, 46), hetIL-15 (47), N-803 (48) and RLI (13, 49) – all have potent anti-metastatic effects, and recently it was reported that multiple peritumoral injections of hetIL-15 showed impressive anti-metastatic activity and a long-lasting specific anti-tumor immunity (31).