The Fatty Acid Composition of the Phosphatides of Normal and Malignant Epidermis1

The fatty acid composition of the lecithins, phosphatidyl serines, phosphatidyl ethanolamines, ceramides, and sphingomyelins of normal and hyperplastic mouse epidermis, squamous cell carcinomas of mice, and tissue-culture-grown squamous cell carcinoma cells of man was determined by gas chromatography. The degree of saturation of the fatty acids of the lecithins, phosphatidyl ethanolamines, and ceramides obtained from squamous cell carcinomas was appreciably greater than that ob tained from these phosphatides of normal mouse epidermis. Fatty acids of the carcinoma phosphatidyl serines were slightly more saturated whereas those of the sphingomyelins were more unsaturated than were the fatty acids of these phosphatides ob tained from epidermis. The fatty acid composition of the phos phatides of squamous carcinoma cells of man grown in tissue culture was vastly different from that observed in normal and hyperplastic mouse epidermis and squamous cell carcinomas of mice. Aside from the increase or decrease in the degree of satura tion of the fatty acids of the various phosphatides in the squa mous cell carcinomas, there were many significant changes in the levels of individual fatty acids in the malignant transformation of epidermis.