Recent Advances and Future Perspectives in Radiolabeled Antibody Fragments for Breast Cancer Molecular Imaging

Breast Cancer (BC) is the leading cause of cancer-related deaths in women and the most common cancer worldwide. It is classified based on its anatomical origin, the presence of Human Epidermal Growth Factor Receptor 2 (HER-2), and the presence of Estrogen Receptor (ER) and/or Progesterone Receptor (PR). Around 20% of breast cancers are HER-2 positive. While biopsy-based diagnoses are valuable in clinical settings, they have limitations in terms of sampling and interpretation. However, laboratory tests such as Immunohistochemistry (IHC) or Fluorescence In Situ Hybridization (FISH) are also limited, including being time-consuming, expensive, and requiring specialized equipment. Ongoing research and technological advancements aim to address the challenges associated with biopsy-based diagnoses and laboratory tests to develop more accurate and efficient methods for assessing HER-2 status. To this end, various radioactively labeled proteins and small compounds, such as single-chain variable Fragments (scFv), F(ab )2, affibody, and nanobody, have been developed to target HER-2 using molecular array techniques. These smaller targeted compounds offer improved image quality, shorter circulating half-life, and reduced immunogenicity compared to their larger counterparts. This is due to their better biodistribution, clearance, and stability. This study investigates the current understanding and ongoing efforts in utilizing antibody fragments for molecular imaging. The specific objectives were to evaluate the advantages of antibody fragments over full-length antibodies regarding biodistribution, clearance, and stability. Additionally, this study aims to assess the current knowledge and ongoing research in utilizing antibody fragments for molecular imaging.