Question

Tumor cells can be identified in PET scan as sites of unusually high 2-[18F]fluoro-2-deoxyglucose (FDG) accumulation, as

• A. Glycolysis occurs at a very high rate in these cells as compared to the normal cells
• B. Glycolysis occurs at a very low rate in these cells as compared to the normal cells
• C. Fluorine inhibits TCA cycle in tumours cells
• D. FDG is not acted upon by the hexokinase enzyme

Hint:

PET scan:
- FDG accumulates in cells with high glycolysis.
- Tumor cells have high glycolysis (Warburg effect).
- FDG is phosphorylated but not metabolized further.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This question tests knowledge of the Warburg effect and PET imaging.

Step 2: Detailed Explanation:
Tumor cells exhibit the "Warburg effect" (aerobic glycolysis).
They have high rates of glucose uptake and glycolysis.
FDG is a glucose analog that is taken up by glucose transporters.
It is phosphorylated by hexokinase to FDG-6-phosphate but cannot be further metabolized.
It accumulates in cells with high glucose metabolism.
Thus, high FDG accumulation indicates high glycolysis rate in tumor cells.
Option A is correct.
Option B is incorrect (glycolysis is high, not low).
Option C is incorrect (fluorine is part of FDG, not an inhibitor).
Option D is incorrect (FDG is phosphorylated by hexokinase).

Step 3: Final Answer:
Thus, tumor cells show high glycolysis rates, which corresponds to option (A).
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