Biochimica et Biophysica Acta 865 (1986) 13-26 13 Elsevier BBA 87151 Inflammatory infiltrates of experimental mammary cancers Wei-Zen Wei, Stuart Ratner, Amy M. Fulton and Gloria H. Heppner Department of Immunology, Michigan Cancer Foundation, 110 E. Warren Avenue, Detroit, MI 48201 (U.S.A.) (Received April 14th, 1986) Contents I. Introduction ............................................................................. II. Lymphocyte infiltrates of murine mammary cancers ................................................. II1. Macrophage infiltrates of routine mammary cancers ................................................. IV. Mechanisms controlling inflammatory cell infiltration and subset distribution ............................... A. Lymphocytes .......................................................................... B. Macrophages .......................................................................... V. Inflammatory infiltrates in neoplastic progression ................................................... VI. Summary ............................................................................... Acknowledgements ............................................................................ References .................................................................................. 13 14 16 17 17 20 22 23 23 24 I. Introduction As is evident by this series of reviews, there is a great deal of interest in the mechanisms of in- flammatory cell infiltration and in the possible roles of inflammatory infiltrates in the develop- ment and growth of neoplasms. The reasons for this interest are obvious - the desire to take therapeutic advantage of whatever opportunities are offered by host 'defense' reactions, the numer- ous, albeit ambiguous, reports that link infiltrates with favorable prognosis, the very presence of the infiltrating cells which challenges researchers to ascribe to them some role or function. Various experimental models have been used to try to define the roles of infiltrating cells; many of these models are described elsewhere in this volume. Among these models murine mammary cancers offer some special advantages, including a well- characterized system for relating inflammatory events to tumor progression and the availability of a range of tumor lines that differ in important phenotypic properties such as immunogenicity and ability to metastasize. It is our contention that the understanding of host infiltrates in cancer can only be achieved in these larger contexts of neop- lastic development and behavior. The purpose of this review is to discuss our findings and those of others on the types of cells that make up inflammatory infiltrates in murine mammary cancers and to present the rather limited data on their possible function and on the mecha- nisms by which they are regulated. 0304-419X/86/$03.50 © 1986 Elsevier Science Publishers (Biomedical Division)