Prostaglandin E2 and cyclic AMP in tumor and plasma of breast cancer patients.

Prostaglandin E2 and cyclic AMP (cAMP) levels were measured in tumors and plasma of 78 patients with benign and malignant breast tumors. Two groups of malignant tissues were found, one with a high level of PGE2 (M = 55.4 pg/mg) and one with a low level (M = 10.7 pg/mg). The low level did not differ significantly from the benign tissue level (M = 8.7 pg/mg). Two malignant groups could not be detected in the plasma levels. Plasma PGE2 concentration (in form of the 13,14-dihydro-15-Keto metabolite) did not reflect the tissue levels, and no difference was found between the benign (M = 59.9 pg/ml) and the malignant (M = 62.3 pg/ml) patients, but both concentrations were higher than those of healthy controls (M = 34.4 pg/ml). The stage of the cancer, the histological classification and, most important, the period of survival, could not be related to the differences in the PGE2 tissue levels. Neither could plasma cAMP be nominated as a breast cancer market because no difference was found between the cAMP levels of benign tumor patients (M = 16.48 pmol/ml), of malignant tumor patients (M = 21.14 pmol/ml) and of healthy controls (M = 19.07 pmol/ml). The conclusion is that although high amounts of PGE2 appear in some malignant breast tumors, they do not affect the clinical situation. These results may explain the failure to treat human breast cancer patients with prostaglandin synthetase inhibitors.