The aim of this study was the evaluation of quantitative changes in the phospholipid fraction of mature erythrocyte membranes in ovarian cancerous women and an attempt to explain these disturbances. Studies were conducted on mature erythrocytes membranes sampled from 70 women with ovarian cancer aged between 24-69 years, treated at the Gynecology Division, Department of Oncology, Karol Marcinkowski University of Medical Sciences in Poznań. 40 patients were diagnosed with a benign neoplasm and 30 with ovarian cancer. Phospholipids from erythrocyte membranes were separated by means of the acidic extraction method, while separation into fractions was performed by means of thin-layer two-dimensional chromatography on plates covered with siliceous gel. Phospholipase C (PLC) activity was determined by means of the Akhrem, s spectrophotometric method. We demonstrated a triple increase in phosphatidylinositol-4-phosphate (Ptd Ins-4-P) and phosphatidylinositol-4,5-diphosphate (Ptd Ins-4,5-P2) in red blood cell membranes of women with benign tumors. Even higher concentrations of these compounds were observed in erythrocyte membranes separated from patients with ovarian cancer with a simultaneous, statistically significant decrease in the level of phosphatidylinositol (Ptd Ins). We also demonstrated an inhibition of phospholipase C activity in erythrocyte membranes. In case of women with benign tumors the decrease in phospholipase C activity was of 18%, whereas red blood cell membranes from women with ovarian cancer showed an inhibition of as much as 71%. These results allow to conclude, that high concentration levels of Ptd Ins-4-P and Ptd Ins-4,5-P2 apart from other factors may be induced by the inhibition of phospholipase C, as phosphate derivates of inositol phospholipids and in particular Ptd Ins-4,5-P2 are PLC substrates.

Keywords: ovarian cancer, erythrocyte membranes, Phospholipids, phospholipase C