arachidonic acid metabolites, PGE2, PGF2 alpha and their metabolites; PGD2, PGI2 and TXB2 will be measured in normal and malignant tissues and in culture fluids after maintenance of these tissues in organ culture. 6-keto-PGF1 alpha, thromboxane B2, PGE2, PGF2 alpha, 15-keto-PGE2, 13,14-dihydro-PGE2, 13,14-dihydro-15-keto-PGE2 and 13,14-dihydro-15-kero-PGF2 alpha are adsorbed on a column of XAD-2 resin; the resin is eluted with ethanol. The metabolites are separated by high pressure liquid chromaography (hplc) on a fatty acid analysis column and the hplc fractions are analyzed by radioimmunoassay with the use of antibodies of appropriate serologic specificiy. The effects of several putative cocarcinogens on this arachidonic acid metabolic cascade are being determined.