Abstract SY20-03: Novel radiotracers for clinical molecular imaging in oncology

Abstract

Abstract In cancer, molecular imaging (MI) can be thought of as imaging the key molecules and molecular based events that are fundamental to promoting and maintaining the malignant state. Although MI is multimodality, the focus of this discussion will be on the use of positron emitting radiotracers for Positron Emission Tomography (PET), an imaging methodogy that can bridge the divide between discovery in the laboratory and application in clinical medicine. Modern PET incorporates CT into the same gantry and as PET/CT has rapidly penetrated clinical oncology, providing improved tumor staging and the detection of recurrence.. F[18]-2-flouro-2-deoxy-D-glucose (FDG) and PET is being used to imaging more tha 1 million cancer patients per year in the US along. The biologic basis for the successful use of FDG-PET/CT is as follows. Many cancers exhibit a characteristic biochemical phenotype, which is altered in comparison to tissues from which the neoplasm originated. In particular, tumor tissues often exhibit the “Warburg Effect” which is an accelerated aerobic glyolysis. The reasons behind the Warburg effect are thought to relate to a need for carbon backbones for tumor growth, as well as to control.altered REDOX state within the cell. Other metabolic markers useful in functional imaging of cancer include radiolabeled nucleosides like [F-18]-Fluorothymidine (FLT) for proliferation, and radiolabeled amino acids, like [C-11] methionine for imaging amino acid transport. Molecular imaging in oncology is increasingly being applied for evaluation of treatment response,to radiation and chemotherapy, using FDG, FLT, and F-18 misonidazole (FMISO) a nitroimidazole which is taken up in hypoxic tissues. Molecular imaging is also applied clinically for drug discovery, and a large number of targeted agents have been radiolabeled and are being studied in man. At MSKCC our group has used PET imaging to study targeting at both a basic and clinical level with a variety of drugs and monoclonal antibodies, includine antibodyA33, which recognizes the epithelial marker A33, and antibody cG250 which recognizes carbonic anydrase IX, a marker of clear cell lung cancer and hypoxia. Finally, endocrine responsive maligancies form a fascinating group for which specific receptor directed agents, and natural substrates, may open a window on the biology of human disease including lesion by lesion heterogeneity. In this regard, [F-18]FDHT, an agent targeting androgen receptor, in prostate cancer and [I-124] NaI, for sodium iodide symporter in thyroid cancer, are giving new information about the behavior of human tumors studied in situ. Citation Format: Steven M. Larson. Novel radiotracers for clinical molecular imaging in oncology [abstract]. In: Proceedings of the AACR 101st Annual Meeting 2010; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr SY20-03