In vivo blockade of IL-2R signalling using blocking antibodies against the IL-2Rβ (also known as CD122) and IL-2Rγc (also known as CD132) chains abrogated the expansion advantage of OT-I TILs in PGE2-deficient Ptgs1/Ptgs2−/− BRAFV600E-OVA tumours (Fig. 4g,h) and that of EP2/EP4-deficient OT-I TILs in PGE2-producing MC38-OVA tumours (Fig. 4i,j). This evidence concerns the gene PTGS1 and neoplasm.