Suppression of glucose utilization of murine peritoneal exudate macrophages by body fluids from cancer patients and identification of the susceptible enzyme.

The glucose consumption of cultured murine (C57BL/6N) peritoneal exudate macrophages is suppressed by pleural effusions, ascitic fluids, and sera from patients with advanced primary lung and gastric cancers. Analysis for the generation of 14C-labeled CO2 after [14C]glucose metabolism revealed the glycolysis pathway to be more susceptible to cancerous body fluids than was the hexose monophosphate shunt. Enzymatic analysis showed that the enzyme susceptible to the cancerous body fluids was D-fructose-6-phosphate 1-phosphotransferase (PFK), the rate-limiting key enzyme in the glycolysis pathway. Other enzymes participating in glycolysis were insensitive to the cancerous body fluids. Suppression of PFK may represent a new tumor marker.