Plasma Fatty Acids as Surrogate for Prostate Levels.

Area of Science:

• Nutrition Science
• Biomarker Research
• Oncology

Background:

• Epidemiologic studies on fatty acids and prostate cancer risk yield inconsistent results.
• Blood fatty acid concentrations are often used as surrogates for prostate tissue concentrations, potentially introducing variability.

Purpose of the Study:

• To assess if plasma phospholipid fatty acid (PLFA) profiles accurately reflect prostate tissue PLFA profiles.
• To determine the reliability of using blood concentrations as surrogate biomarkers for prostate tissue fatty acid composition.

Main Methods:

• Analyzed PLFA profiles in plasma and prostate tissue from 20 prostatectomy patients.
• Collected multiple prostate tissue specimens per patient to assess homogeneity.
• Calculated correlations between tissue specimens by size, individual tissue samples (ICC), and plasma vs. mean tissue concentrations.

Main Results:

• PLFA concentrations were consistent across different tissue specimen sizes (≤ 20 mg vs. > 20 mg).
• High intra-individual correlations were observed between most tissue specimens (e.g., eicosapentaenoic acid = 0.96).
• Strong correlations were found between mean tissue and plasma PLFA concentrations for most fatty acids (e.g., eicosapentaenoic acid = 0.93).

Conclusions:

• Prostate tissue PLFA concentrations are largely homogeneous and reliably measurable even in small samples.
• Plasma PLFA concentrations serve as adequate surrogate markers for most individual PLFAs in prostate tissue.
• These findings can improve the accuracy of future epidemiologic studies on fatty acids and prostate cancer risk.