Prostacyclin and thromboxane synthesis by endometrial cancer and leiomyomas

To study the role of prostacyclin (PGI2) and thromboxane A2 (TxA2) in uterine tumors, pieces of endometrial cancer (n = 12) and leiomyomas (n = 12) were incubated in vitro, and the productions of 6-keto-prostaglandin F1a (6-keto-PGF1a, a hydration product of PGI2) and thromboxane B2 (TxB2, a hydration product of TxA2), measured by radioimmunoassay, were compared to those of corresponding healthy tissues. The production of 6-keto-PGF1a by endometrial cancer (20.8; 15.1-85.0 ng/mg protein/min, median and interquartile range), by healthy endometrium (25.5; 10.0-55.0), by healthy myometrium (34.9; 25.0-59.9) and by leiomyoma (20.3; 10.2-45.1) was similar. The production of TxB2 was increased by endometrial cancer (55.5; 10.5-155.2, p less than 0.02) in comparison with endometrium (9.8; 4.3-35.1), myometrium (3.8; 2.1-8.0) and leiomyoma (1.9; 1.0-3.8). The 6-keto-PGF1a/TxB2 ratio in endometrial cancer (0.9; 0.3-1.5) was smaller (p less than 0.02) than that in healthy endometrium (3.3; 1.9-4.8). Thus, TxA2 may be a factor in endometrial cancer.