Furthermore, additional studies are still needed to expand our understanding of the complex mechanisms involved in the function and interaction of infiltrating CD4+ T-lymphocytes, their cytokine biosynthesis, as they relate to increased malignancy and metastasis, and of the role played by CD8+ T-cells in inhibiting tumor development, determining the tumor microenvironment that favor the control mechanisms in canine mammary carcinomas. The gene discussed is CD4; the disease is breast carcinoma.