As a result of clinical assays, the immunomodulator action of PSK has been proposed as an agent that can induce the expression of the interleukin-8 gene (IL-8) in peripheral blood mononuclear cells (PBMCs) after oral administration by stimulating T cell proliferation and enhancing the function of T CD4+ cells in the intestine and associated lymphoid tissue [27,28,29,30], while also significantly prolonging the survival of patients with stomach, colorectal, and lung cancer [31,32,33]. Here, CXCL8 is linked to lung cancer.