CD8A and neoplasm: Additional immunohistochemistry for Ly6G and CD8a in 4T1 + RAW264.7 and 4T1 primary tumors also showed few staining around the tumor-harboring mammary ducts at 1 w p.i. However, at 3 and 5 w p.i. the Ly6G and CD8a positivity increased and, in marked contrast to CD163, were located within the primary tumor area.