NOS2 and fibrosarcoma: In contrast, the iNOS null fibrosarcoma cell line (KX-dw1, KX-dw4, and KX-dw7) and M5076 murine ovarian sarcoma cell lines injected into iNOS( ̄/ ̄) mice showed more tumourigenicity and lung metastasis as compared to iNOS(+/+) counterparts [203,204].