18F-fluorodeoxyglucose PET imaging exploits the metabolic phenotype of many cancers. The high tumor uptake of FDG depends chiefly on which two properties of transformed cells?

• A Reduced glucose-6-phosphatase and enhanced gluconeogenic flux
• B Loss of lactate dehydrogenase and increased pyruvate carboxylase activity
• C Increased fructose transporter GLUT5 and elevated aldolase B levels
• D Upregulated GLUT1 transporters and increased hexokinase activity ✓

Explanation

Warburg-type tumors overexpress GLUT1 and show high hexokinase (especially HK2) activity, so FDG is transported and phosphorylated to FDG-6-phosphate, which cannot proceed down glycolysis and is trapped intracellularly, generating the PET signal. GLUT5 handles fructose, not glucose analogues, and gluconeogenic enzymes are irrelevant because tumors do not dephosphorylate the trapped tracer.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.