Here, by the integration of functional and molecular data obtained leveraging preclinical murine and human breast tumor models, we reveal that, in addition to its cell-autonomous ability to negative modulate oncogenic signaling pathways, p140Cap also influences cell-extrinsic events by suppressing a tumor permissive immune response in favor of an efficient anti-tumor response in the TME of the primary tumor. The gene discussed is SRCIN1; the disease is neoplasm.