The increased density of fibrillar structures of the tumor ECM is determined primarily by the orientation and density of collagen fibres and the spacing between them, all of which influence the distribution and migration of cytotoxic lymphocytes, CD8+ cytotoxic T lymphocytes (CTLs) and NK cells within the tumor stroma (Du et al., 2024; Cho and Doh, 2024). The gene discussed is CD8A; the disease is neoplasm.