PTGER4 and neoplasm: PTGER4 can downregulate the expression of the IL-2Rγc chain, inhibiting the response of tumor-infiltrating lymphocytes (TILs) to IL-2 in tumor tissues; this leads to a defect in the assembly of the IL-2Rβ-IL-2Rγc dimer on the cell membrane, thereby inhibiting the response of CD8+ T cells to IL-2 (126).