An elongation factor-like protein (EF-Tu) elicits a humoral response in infiltrating ductal breast carcinomas: an immunoproteomics investigation.

In the current study, we have used an immunoproteomics approach to identify proteins that commonly elicit a humoral response in patients with infiltrating ductal carcinomas of the breast. Sera obtained at the time of diagnosis from 40 patients with invasive breast cancer and 42 healthy controls were screened for the presence of IgG antibodies to MCF-7 cell line proteins using a serological proteomics-based approach. An immunoreactive protein detected in sera from 21 of 40 patients was isolated and subsequently identified as elongation factor-Tu. The immunoproteomic approach implemented here offers a powerful tool for determining novel tumor antigens that induce a humoral immune response in cancer patients. From our findings, the immunoreactive EF-Tu protein and/or the related circulating antibodies may display clinical usefulness as potential diagnostic markers and provide a means for a better understanding of the molecular mechanisms underlying breast cancer development.