Relationship between blood plasma prostaglandin E2 and liver and lung metastases in colorectal cancer. The relationship of prostaglandin E2, of which a large amount is produced in various neoplasms, and hematogenous distant metastases was investigated in a total of 44 colorectal cancer patients because of its varied pathophysiologic potentials. The authors found significantly high levels of PGE2 in local venous blood draining the carcinoma and in peripheral blood in cases with liver or lung metastasis, as well as a significantly large amount of PGE2 production in the carcinoma tissue. The results suggest that increased local blood PGE2 could enhance the metastasis formation, and increased peripheral blood PGE2 may be useful in the detection of such metastasis in colorectal cancer. 