A comparative immunofluorescence analysis of three clinical-stage antibodies in head and neck cancer

Background: The antibody-based targeted delivery of bioactive molecules to tumour vasculature is an attractive avenue to concentrate therapeutic agents at cancer sites, while sparing normal organs. L19, F8 and F16 are three fully human monoclonal antibodies, specific to splice isoforms of fibronectin and tenascin-C, which bind to sites of active tissue remodeling and which are currently in Phase I and II clinical trials as radio-immunoconjugates and immunocytokines in patients with cancer and arthritis. In this article, we report the first comparative analysis of expression patterns for the extra domains EDB and EDA of fibronectin and A1 of tenascin-C in both primary and metastatic head and neck cancer lesions. Methods: We performed a comparative immunofluorescence analysis with the L19, F8 and F16 antibodies in 40 freshly frozen human head and neck cancer specimens. Results: On average, F8 and F16 exhibited similar staining intensities, which were typically stronger than L19. Interestingly, some specimens exhibited striking differences in staining by the three antibodies. Conclusions: These results suggests that an individualized treatment procedure (e.g., choice of L19, F8 or F16 based on immuno-PET or immunofluorescence procedure) may represent the most logical avenue for offering the best possible antibody to any given patient.