Here, using immunocompetent Cav-2 KO mice as a unique model of a robust anti-tumor response to the implanted syngeneic lung carcinoma, we show for the first time that before starting to regress, the early stage tumors display an enhanced macrophage infiltration with M1-like phenotype followed by increased CD4 and CD8 T cell infiltration. The gene discussed is CD4; the disease is lung carcinoma.