IL4 and neoplasm: Th1 cells suppress malignant tumor proliferation via inducing an immune response to tumors by mainly secreting interferon‐γ (IFN‐γ) and tumor necrosis factor‐α (TNF‐α); while Th2 cells mainly secrete interleukin‐4 (IL4), IL‐10 leading to tumor immunosuppression.30