Comparison of Invasive TAM sub-population to General TAM population

The tumor microenvironment modifies the malignancy of tumors. In solid tumors this environment is populated by many macrophages (tumor-associated macrophages; TAMs) that in genetic studies that depleted these cells from mouse models of breast cancer were shown to promote tumor progression to malignancy and increase metastatic potential. Mechanistic studies showed that these effects are through the stimulation of tumor cell migration, invasion, intravasation as well as an enhancement of angiogenesis. Using an in vivo invasion assay it was demonstrated that invasive carcinoma cells are a unique sub-population of tumor cells whose invasion and chemotaxis is dependent upon the co-migration of TAMs with obligate reciprocal signaling through an EGF/CSF-1 paracrine loop. In this study these invasion-promoting macrophages were isolated and subjected to analysis of their transcriptome in comparison to TAMs isolated indiscriminately to function using established macrophage markers by flow cytometry. Five biological replicates for each population (Invasive and General TAM) were used.