CD8A and breast cancer: CD5 is a glycoprotein receptor on the surface of T lymphocytes.[66] A recent study found that the use of function-blocking anti-CD5 monoclonal antibody or the knockout of CD5 inhibits tumor growth in a breast cancer mouse model by enhancing the capability of CD8+ T cells.[67] Hosaka et al. detected the expression of CD5 in both thymic cancer tissue and lymphoid stroma.