CD4 and neoplasm: Compared with the corresponding PBL or TILs, in the SLNs, the proportions of B lymphocytes, CD3+CD4+ and CD4+CD69+ T lymphocytes, together with the CD4+/CD8+ ratio, are significantly higher; this result reflects the preferable selection of T helper cells and B lymphocytes by the SLN microenvironment to enhance tumor antigen-presenting activity and anti-tumor immune regulation.