An autoantibody against a 48-Kd fragment of human DNA-topoiomerase I in breast cancer: Implication for diagnosis and prognosis, and antibody-dependent cellular cytotoxicity in vitro

[Display omitted] •Anti-TOPO48 autoantibody can be used as a potential biomarker for early diagnosis of breast cancer.•Anti-TOPO48 autoantibody is a potential biomarker indicating favorable prognosis of BC patients.•Anti-TOPO48 autoantibody can induce significant ADCC activities to destroy BC cells in vitro.•ADCC activities are significantly correlated with NK cells, NKT cells, and CD4+/CD8+ T cells.•Anti-TOPO48 autoantibody represents an early index of immune response to the TAA.•Anti-TOPO48 autoantibody also involves in host immune defense mechanisms to destroy cancer cells. Previously, we reported a novel tumor-associated antigen (TAA) derived from human DNA-topoiomerase I (TOP 1). In the present study, we demonstrated that the autoantibody against the TAA could be a potential biomarker in the early diagnosis and favorable prognosis of patients with breast cancer (BC). To understand the survival benefits in BC patients, we investigated whether the autoantibody could induce antibody-dependent cellular cytotoxicity activities (ADCC) against breast cancer cells in vitro. We found that the autoantibody exhibited significant ADCC activities that destroyed breast cancer MCF-7 and MDA-MB-231cells with peripheral blood mononuclear cells (PBMCs). The ADCC activities of the autoantibody were significantly correlated with the number of natural killer (NK) cells, NKT cells, and CD4+/CD8+ T cells. Accordingly, our findings showed that the autoantibody not only represented an early index of immune response to the TAA, but also was involved in host immune defense mechanisms that initiated the destruction of cancer cells.