IL6 and neoplasm: Macrophages are phagocytic cells, which have been considered for cancer immunotherapy in recent years, as they play an important role in host immune defence systems by killing tumour cells via phagocytosis, and releasing tumour-killing molecules, such as nitric oxide (NO), tumour necrosis factor (TNF-α), reactive oxygen species (ROS), interleukin (IL)-1β, and IL-6 [64].