However, it is well known that cancer cells can secrete inflammatory factors such as interleukin (IL)-1, IL-2, IL-6, IL-8, IL-12, IL-17, granulocyte colony-stimulating factor, and tumor necrosis factor-alpha, which may contribute to the tumor microenvironment, leading to tumor invasion, leukocytosis, and thrombocytosis (4,21). Here, IL2 is linked to cancer.