The cell of particular research interest to Dr. Schwertfeger is the macrophage, a specialized innate immune system cell. Macrophages circulate as monocytes in the blood and are recruited to different tissue sites as part of an immune response. Macrophages have long been known to be associated with tumors, initially it was thought to attack tumors. More recently scientists have found that macrophage populations at a tumor site is reflective of tumor size and aggressiveness, suggesting the possibility that macrophages may serve to promote tumor growth rather than attacking tumors. It is now understood that macrophages are recruited by tumors through signaling mechanisms and commandeered to assist in tumor expansion and metastasis.
Schwertfeger and her colleagues are interested in the mechanisms that drive macrophage-tumor cell interactions and the internal signaling in macrophages that causes them to respond the way they do in the tumor microenvironment. If signaling mechanisms can be identified, they could be targets for therapeutic intervention. Macrophages, literally "big eaters," are large cells that normally engulf and digest cellular debris and foreign material and could potentially be turned against the tumor. Researchers have tended to focus on the soluble growth factors macrophages produce as part of their normal functions rather than signaling pathways that could reveal how and why they produce these factors. Schwertfeger's team is currently exploring three macrophage signaling molecules involved in normal macrophage functioning and that of other cell types. Schwertfeger's laboratory is also exploring how breast cancer cells interact with osteoclasts to promote bone metastasis using the FGFR signaling pathway.
