Micro PET imaging of 18F-Fluoromisonidazole in an MDA-MB-231 triple negative human breast cancer xenograft model

Hypoxia is a pathophysiological property that is defined as a state of depressed oxygen tension. The aberrant growth of tumors exacerbates their susceptibility to hypoxia, especially for malignant solid tumors (1). Since it is well known that hypoxic cancer tissues are more resistant to radiotherapy and chemotherapy than aerobic tissues, tumor hypoxia is often an important determinant of relapse-free survival and overall clinical outcome (2-4). The onset of hypoxia in tumors is associated with and influenced by a sequence of complicated and physiological processes, and could significantly affects the curability of solid tumors, regardless of treatment modality employed (1). So far, several methods exist to characterize hypoxia directly or indirectly. The polarographic electrode is an invasive, yet direct method for pO2 measurement, and is often cited as the “gold standard” for hypoxia determination (5). But this method is invasive and can only be used in superficial tumors, does not distinguish between necrotic and viable tissue. Noninvasive imaging of hypoxic cancer cells is of extremely clinical importance for both diagnosis and therapeutic evaluation