Membrane vesicles in ovarian cancer fluids: a new potential marker

The rate of membrane vesicle shedding by tumor cells is probably related to their invasive capability. In order to verify whether the vesicle amount could be utilized as a marker of different pathologies, we analyzed biological fluids obtained from 33 patients with gynecological diseases. In fluids of benign serous cysts, vesicle content was extremely low; in cystoadenomas and fibromas generally it was low. On the contrary, large amounts of vesicles were found in malignant tumor fluids. Gelatin zymographies showed the presence of MMP-2 and MMP-9 in all vesicles except in those recovered from fluids of some serous cysts. A positive correlation between tumor malignancy and both vesicle-amount and vesicle-associated MMP-2 activity was noticed. We also analyzed vesicle content in ascitic fluids recovered from two carcinomas at different times during clinical treatment. In both cases, tumor progression, not monitored by Ca 125 levels, was pointed out by an increased amount of vesicles in ascites. These findings suggest that vesicle content in biological fluids could represent a new useful marker of tumor aggressiveness and tumor progression.