ShcA is a Paracrine Integrator of the Adaptive Immune Response during Breast Cancer Progression

Using transgenic mouse models of breast cancer, we demonstrate that loss of ShcA signaling within mammary tumors results in extensive CD4+ T cell infiltration, activation and induction of a humoral immune response. Our studies reveal that ShcA signaling during early breast cancer progression is required to establish and maintain an immunosuppressive state that favors tumor growth. Consistent with these transgenic studies, high ShcA levels correlate with poor outcome and reduced CTL infiltration in primary human breast cancers. Conversely, elevated expression of a ShcA-regulated immune signature, generated from ShcA-null mammary tumors, is a predictor of good prognosis in HER2-positive and basal breast cancer patients. These observations define a novel role for ShcA in polarizing the immune response to facilitate tumorigenesis NIC SHC null Tumors vs. pooled MMPV-NIC reference, some replicate dye swaps