Hematopoietic stem cell-derived adipocytes and fibroblasts in the tumor microenvironment

Figure 2 Origins of cancer-associated adipocytes and cancer-associated fibroblasts. This drawing illustrates the complex and ever-growing understanding of the origins for cancer-associated adipocytes (CAAs) and cancer-associated fibroblasts (CAFs). CAAs and CAFs are generally thought to arise from resident tissue cells, the adipose stem cell (ASC) and resident fibroblast, respectively. However, alternative sources for adipocytes and CAAs have been demonstrated including cells of the bone marrow, specifically those of the myeloid lineage (e.g., macrophages, CFPs, and fibrocytes). In addition to resident fibroblasts, CAFs have been shown to be derived from myeloid progenitors (CFPs, fibrocytes), mesenchymal stromal cells (MSCs), ASCs, CAAs, epithelial cells, tumor cells, and endothelial cells. It is possible that these multiple sources are reflected in the morphological, phenotypic, and functional heterogeneity described for adipocytes and for CAFs. HSC: Hematopoietic stem cell; CFPs: Circulating fibroblast precursors.