A Breast Cancer Update
With Breast Cancer Awareness Month in full swing, some of the latest research in this area is hereby presented. A more recent approach to cancer is the development of a vaccine, and Sellas Pharmaceuticals has a breast cancer vaccine in development which is combination immunotherapy, the mixture of a peptide antigen, the NeuVaxTM vaccine, and an antibody, Herceptin® (a Genentech/Roche product). It is currently in Phase 2b and aims to target HER2/neu. Cytotoxic T-lymphocytes (CTLs) target the epitope, KIFGSLAFL or HER-2 (369-377) HLA-A2–binding peptide, thereby killing cells that overexpress HER2/neu. This overexpression is a common feature of breast and other cancers. HER2/neu breast cancers have a high chance of relapse and the vaccine aims to prevent that from occurring.1
Another approach also targets the overexpression of HER2, but this time it aims to use a radiolabeled peptide to bind to and identify the overexpression using molecular imaging. They use tumor-associated antigens, which are less cytotoxic than other therapies. Peptides have the advantage of specific targeting, quick clearance, small size, low immunogenicity, and many more desirable features. Another protein that is often overexpressed in cancers is human epithelial mucin-1 (MUC1) and is another possible antigen target. Peptides targeting HER2 (Ac-GGCAKIFGSLAFLKCCYSL-NH2) and MUC1 (Ac-GGCEPDTRP-NH2) were labeled with 99mTc by use of a GGC chelating sequence and could be seen using γ-camera imaging. The peptides showed good metabolic and radiochemical stability. They are a first step to designing tumor-targeting peptides in breast cancer imaging.2
- A.M. Henle, et al, J Immunol, 190 (1), 479 (2013).
- S.M. Okarvi & I. AlJammaz, Molecules, 24, 3142, (2019).