ADIPOSITY-RELATED CANCER AND FUNCTIONAL IMAGING OF BROWN ADIPOSE TISSUE

OBJECTIVE: Brown adipose tissue (BAT) is involved in energy dissipation and cytokine production and is potentially beneficial for the human body. The aim of the paper is to review the literature on adiposity-related cancer and functional imaging of BAT.

METHODS: We performed a review on adiposity-related cancer and functional imaging of BAT. We extensively researched papers for information on BAT molecular biology, as well as functional imaging modalities.

RESULTS: Adipose tissue is linked to the development of many cancers. Multiple drugs including fenofibrate, spironolactone, and other substances, as well as experimental agents like β-3 receptor agonists, caffeine, green tea extract, medium chain triglycerides (MCTs), and adenosine are known to stimulate and activate BAT. However, cold and nonshivering thermogenesis are the main activators of BAT. BAT has been detected on both magnetic resonance imaging (MRI) and 18F-fluorodexoxyglucose positron emission tomography (18F-FDG-PET)-based imaging in multiple studies. Different methods of cold stimulation and static and dynamic protocols have been used to detect and image BAT. Factors like sex, fasting or fed state, surface skin temperature, and/or body mass index (BMI) may influence PET-based BAT detection. BAT has also been detected using MRI, (99m)Technetium (Tc)-sestamibi, and 123I-metaiodobenzylguanidine single-photon emission computed tomography/computed tomography (MIBG SPECT/CT).

CONCLUSIONS: Stimulation of BAT offers promise in the management of obesity-related conditions. Tracers like [(15)O]-H2O, [(11)C] acetate, and 18F-fluoro-6-thia-heptadecanoic acid (18F-FTHA) that measure BAT blood flow, oxygen utilization, and nonessential fatty acid (NEFA) uptake, respectively, have been studied in humans. Future studies should focus on BAT tissue generation by altering the genetic pathways of adiposity-linked genes.