NOS2 and Carcinoma, Lewis Lung: Interestingly, when transferring iNOS deficient (Nos2-/-) or wild-type bone marrow cells into irradiated recipient mice followed by Lewis lung carcinoma establishment, mice reconstituted with NOS2-deficient bone marrow cells had fewer M1 and similar numbers of M2 macrophages than mice reconstituted with bone marrow from wild-type mice.