Peripheral Serum From Breast Implant–Exposed Patients Decreases Breast Cancer Cell Viability: Evidence for Immunosurveillance

Epidemiologic and preclinical studies suggest a potential protective effect of breast implants against breast cancer, but underlying mechanisms remain unclear. The authors hypothesize that local inflammation after breast implant placement induces immunosurveillence. The authors of this study investigated whether serum from implant-exposed (IE) women reduced breast cancer cell viability compared with implant-naive (IN) women, and whether antibodies mediated this effect. Serum from IE and IN women with high or low antibody levels against estrogen receptor-alpha, mucin-1, or mammaglobin-A was incubated with cancer cell lines overexpressing each antigen (MCF7, T47D, and SKBR3, respectively). 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assays measured cell viability. Rescue experiments utilized recombinant antigen to neutralize antibodies. Thirty-six patients were enrolled, and 12 samples were used to assess viability for each cell line. Serum with high antibody concentrations reduced cell viability compared with serum with low antibody concentrations across all cell lines. IE serum reduced cell viability compared with IN serum across all cell lines. Rescue experiments reversed differences between high and low antibody serum, as well as between IE and IN serum, implicating antibodies as the mediators of reduced viability. Peripheral serum from IE women decreased breast cancer cell viability compared with IN women, even when matched for the same antibody levels. Antibody neutralization reversed differences. This suggests implant exposure altered antibody function or other serum components. These findings support the hypothesis that the inflammatory response to breast implants may increase breast cancer immunosurveillance, although significantly more work is needed to confirm a mechanism. Level of Evidence: 3 (Therapeutic).