CCL2 and cancer: Fibroblasts were clustered into three different subtypes (Figure 4A): a) PDGFRA+ fibroblasts, which exhibit strong expression of major collagen genes including COL1A1, COL1A2, and COL3A1; b) RGS5+ fibroblasts, which have characteristics similar to vascular smooth muscle cells with expressions of ACTA2, TAGLN, and MTY11; and c) inflammatory fibroblasts, which strongly express chemokines including CCL2, CXCL2, CXCL8, and IL6, suggesting these cells were in an active cytokine‐producing state and similar to cancer‐associated fibroblasts described in many studies[22] (Figure 4E).