Summary— Prostaglandins have been implicated in the development and spread of malignant tumours. Gas chromatography and mass spectrometry (GC-MS) analysis of prostaglandins in benign and malignant prostatic tissue showed that prostacyclin (PGI2), a prostanoid known to induce bone resorption, was the major component. PGI2 is hydrolysed to 6-oxo-PGF1a. Plasma levels of 6-oxo-PFG1a were measured as an index of PGI2 formation in patients with benign and malignant prostatic disease.

The mean plasma 6-oxo- level in an age-matched control group was comparable to that of patients with benign prostatic hypertrophy. A significant elevation was found in patients with a TO carcinoma (P<0.05). Plasma 6-oxo- levels rise with advancing disease and the concentration varied with the degree of tumour differentiation. Plasma 6-oxo- levels were a more accurate monitor of disease progression than tartrate labile acid phosphatase in patients with M1 carcinoma. Persistently elevated levels were associated with a bad prognosis.