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From: Heterotypic signaling of cancer-associated fibroblasts in shaping the cancer cell drug resistance
Figure 1. Origin and heterogeneity of cancer-associated fibroblasts. CAFs in the tumor microenvironment can be originated from MSCs, fibroblasts, adipocytes, pericytes, smooth muscle, endothelial and epithelial cells through the different trans-differentiation programs. Varieties of CAF subsets have been identified in cancer types of different tissue origins. The different subsets of CAFs show different functions and molecular features. CAF-S1 to CAF-S4 subsets are present in breast cancer. myCAF, iCAF and apCAF subsets are observed in PDAC. Several cancers exhibit overlapping populations of CAF subsets.