Tumor-Associated Macrophage Isolation and In Vivo Analysis of Their Tumor-Promoting Activity

Characterization of individual cell populations from the tumor microenvironment is critical to understand their functional contribution to tumor progression. Magnetic bead enrichment and fluorescence-activated cell sorting (FACS) allow for the isolation of specific cell types that can be used in downstream applications, including in vitro and in vivo functional studies and molecular profiling. In this chapter, we describe the process of isolation of tumor-associated macrophages (TAMs) from primary murine breast tumors subsequent to therapeutic or experimental intervention. Additionally, we further detail how to analyze their ability to support tumor cell growth by co-injecting isolated TAMs with tumor cells orthotopically into the mammary gland of immune-deficient hosts, and monitoring tumor progression by live imaging and caliper measurement.