PTGS2 and neoplasm: We demonstrated that CTCF‐transcribed LncRNA PACERR directly interacts with CTCF, and the CTCF/PACERR complex recruits the acetyltransferase EP300 to increase the chromatic accessibility of PTGS2 locus, resulting in upregulated PTGS2 expression, thereby promoting the M2 polarization and pro‐tumour functions of TAMs.