FIG. 7.

Young ER-α⁺ breast tumor stroma exhibits significant differences in specific matrix components and immune cell types. Young tumor stroma (<45 years old) revealed significantly higher levels of matrix components (fibronectin, integrin α and β, collagen III, collagen V, collagen VI, collagen VII, and laminins A, B, and C) and immune cell types (CD8⁺ T cells and T_H2 cells) (*P < 0.05). Aged tumor stroma (>65 years old) revealed a significantly higher M2 macrophage infiltrate (*P < 0.05) compared to young stroma. The young and aged tumor stroma exhibit comparable numbers for MSC and adipocyte infiltrate; however, young MSCs may exhibit a greater potency and stimulate a rapid estrogen signaling pathway through cytokine and growth factor secretions. The activation of ER-α through ser-167 phosphorylation by another signaling pathway may be an underlying factor for the increased ER-α signaling and increased proliferation observed in MCF-7 cells stimulated with young CM compared to those stimulated with aged CM. Created with Biorender.com