The role of molecular imaging in the development of dendritic cell-based cancer vaccines

Abstract

This editorial aims to highlight some of the general aspects underlying the development and use of dendritic cell (DC) vaccines against cancer and to review the main work that has been carried out in this field using molecular imaging techniques. It stems from the paper by Quillien et al. [1], published in this issue of Eur J Nucl Med Mol Imaging, describing a study in which, in the context of a vaccine therapy protocol for melanoma, mature DCs were labelled with In-oxine and administered to patients via three different routes: lymphatic vessel, lymph node and intradermally. The authors showed that intralymphatic vessel injection can convey a large and precise quantity of DCs in a reproducible way to around ten nodes. In some cases, injection by the intranodal route gives a similar result, but this technique is not reproducible. Finally, they showed, for the first time in humans, that DCs with TH1 cell polarisation capacities can migrate to lymph nodes after intradermal injection. The paper by Quillien et al. [1] is a methodologically complex study, yet straightforward and conceptually simple, which underscores three facts: first, immunology holds great potential in cancer treatment, as immunotherapy is one of the new frontiers in cancer treatment, along with surgery, chemotherapy and precision radiation therapy; second, molecular imaging techniques can make very effective and unique contributions in addressing issues related to the development of cancer treatment; third, curiosity-driven researchers in immunology and molecular imaging are working closely together to devise research strategies for the development and effective use of image-supported immunotherapy. There is indeed already a long tradition of collaboration between researchers in the fields of molecular imaging and immunology, as demonstrated by the development and use of radiolabelled monoclonal antibodies and by other studies that have assessed the immune system components and functions in vivo by means of radionuclide imaging, including previous studies with radiolabelled DCs. Thus, the paper of Quillien et al. [1] is just a further example of a study that will stimulate the interest of researchers to examine unsolved issues in the area of in vivo radio-immunology with DCs. It is worth noting that the use of DCs for cancer vaccination is only one of the numerous tracks being followed by researchers in the development of anti-cancer vaccines. Many other routes for vaccine development are being pursued by the use of cells, peptides, proteins, DNA and recombinant viral vectors. A full appreciation of the advances in the field of immunology and in particular in the field of vaccine development can be found elsewhere [2–5]; thus only a summary of the known role of DCs and their use in cancer vaccination will be provided.