To study the specific functions of Th17 cells in the DLBCL microenvironment, typical intracellular cytokines related to Th17cells, including IL-17A, IFN-γ, and FOXP3 were analyzed by immunohistochemistry (IHC) in paraffin-embedded tumor specimens from 48 DLBCL patients and benign lymph node specimens from 18 controls. The gene discussed is FOXP3; the disease is neoplasm.