Effect of radiotherapy and chemotherapy on composition of tumor membrane phospholipids.

Phospholipid extracts were made of a murine mammary adenocarcinoma implanted in the dorsum of the foot of C3H/He mice before and 96 h after 17 Gy irradiation or 150 mg/kg cyclophosphamide. Extracts of untreated tumors, which had grown for a further 96 h, were also studied. Although previous studies have shown significant changes in the precursors and catabolites of phosphatidylcholine and phosphatidylethanolamine following therapy, 31P nuclear magnetic resonance analysis of extracts showed no changes in these membrane constituents and other observed phospholipid species. A significant decrease in 1-alkyl-2-acyl-sn-glycero-3-phosphocholine, however, was observed 96 h following cyclophosphamide treatment.