ELN and neoplasm: This tumor stroma is basically composed of the non-malignant cells (stromal cells) of the tumor such as cancer-associated fibroblasts (CAFs), immune cells [tumor-associated macrophages (TAMs) and tumor-associated neutrophils (TANs)], and mesenchymal stem cells as well as the extracellular matrix (ECM) consisting of fibrous structural proteins (collagen and elastin), fibrous adhesive proteins (fibronectin and laminin), and proteoglycans (1–, 3) (Figure 1A).