A comparative study of tissue ω-6 and ω-3 polyunsaturated fatty acids (PUFA) in benign and malignant pathologic stage pT2a radical prostatectomy specimens.

To analyze different polyunsaturated fatty acid (PUFA) tissue levels in malignant compared with benign prostatic tissue from the same prostate specimens. Fresh frozen benign and malignant prostatic tissue was obtained from radical prostatectomy specimens in 49 men with pathologic stage pT2a prostate cancer. Histopathologic examination confirmed that all tissues from each prostate being analyzed were either completely benign or almost totally malignant. The PUFA composition in these tissues was determined by gas-liquid chromatography on a capillary column. The relative amount of each PUFA (% of total fatty acids) was quantified by integrating the area under the peak and dividing the result by the total area of all fatty acids. Tissue levels of dihomo-γ-linolenic acid, (C20:3w6), an ω-6 PUFA and a major precursor of ω-6 PUFA metabolites, were significantly higher in malignant compared with benign tissues (P = 0.002). Tissue levels of the downstream ω-6 metabolites, arachidonic acid (AA) (20:4ω6), and adrenic acid, (22:4ω6), were significantly lower in cancer tissues, (P < 0.0001 and P = 0.013, respectively). Overall, the total levels of ω-6 PUFA were lower in cancer (P = 0.001). We found that the ω-6 PUFA AA and adrenic acid are decreased in malignant prostatic tissues compared with benign tissues from the same prostates. These findings provide additional evidence that dietary fat is associated with prostatic carcinogenesis.