Anti-HERV-K antibodies have also been detected in breast cancer patients [16,64], and peripheral blood mononuclear cells (PBMC) from breast cancer patients stimulated in vitro with HERV-K are able to induce T-cell responses, such as T-cell proliferation, IFN-γ production and proinflammatory cytokine secretion [16]. Here, IFNG is linked to breast cancer.