PTPRC and neoplasm: In murine models, it was previously found that tumor matrix tracks, rich in TNC and untensed Fibronectin fibers, play a role in the immunomodulation of the tumor microenvironment by entrapping immune cells.[57, 75] Representative confocal images stained for cytotoxic T cells (CD45+ & CD8+) and regulatory T cells (Tregs) (CD4+ & FoxP3+) in invasive human carcinomas now show close proximity between both immune cell types and FnBPA5‐positive Fibronectin fibers (Figure6A,B).