PTGS2 and neoplasm: Interestingly, many pro-inflammatory factors, such as Cxcl2, Cxcl5 and Cox-2, were upregulated even in non-tumor tissues in the absence of IFN-γ receptor, suggesting that in addition to being favorable for tumor progression, the microenvironment in the intestines of Ifngr1−/−mice may also be conducive to tumor initiation.