Abstract 1871: Circulating cis- and trans- palmitoleic acid in relation to prostate cancer-specific mortality among prostate cancer patients

Background: Palmitoleic acid (16:1n-7c), a lipokine, and its trans isomer (16:1n-7t), a fatty acid found in foods of ruminant origin, have been associated with metabolic regulation and insulin sensitivity, which have in turn been related to prostate cancer progression and survivorship. Objective: To investigate whether circulating cis- and trans-palmitoleate, measured before and after prostate cancer diagnosis, are related to prostate cancer-specific mortality among men diagnosed with non-metastatic prostate cancer. Methods: We employed a prospective study using pre-diagnostic whole blood samples collected in 1982 in 518 men who were later diagnosed with prostate cancer and followed for mortality. Proportional hazards regression was used to estimate relative risk (RR) and 95% confidence interval (CI) of prostate cancer-specific mortality across quartiles of pre-diagnostic palmitoleate concentrations. The multivariable model was adjusted for age at diagnosis, BMI, smoking status, clinical characteristics and time interval between blood drawn and prostate cancer diagnosis. Using a nested case-control design, we also assayed 148 post-diagnostic red blood cell samples collected in 1997 among 74 patients who subsequently died of the disease and 74 survivors, matched with age at diagnosis and risk scores. Conditional logistic regression was used to estimate the RR (95%CI) of prostate cancer-specific mortality across tertiles of post-diagnostic palmitoleate levels after adjusting for BMI and smoking status. trans- and cis-palmitoleic acid concentrations were measured by gas chromatography. Results: Pre-diagnostic whole blood trans-palmitoleic acid and post-diagnostic red blood cell trans-palmitoleic acid levels were associated with lower prostate cancer-specific mortality. The adjusted RR (95%CI) of prostate cancer-specific mortality comparing top to bottom quartiles of pre-diagnostic 16:1n-7t was 0.35 (0.16-0.79; p-trend = 0.03). The adjusted RR (95%CI) comparing top to bottom tertiles of post-diagnostic 16:1n-7t levels was 0.26 (0.08-0.84; p-trend = 0.02). In contrast, cis-palmitoleic acid levels measured before and after prostate cancer diagnosis were unrelated to disease-specific mortality. The pre-diagnostic cis-isomer, however, was significantly correlated with a lower level of adiponectin and higher levels of C-peptide, insulin-like growth factor binding protein 3, and pro-insulin. Conclusions: Pre- and post- diagnostic circulating trans-palmitoleic acid, but not cis-palmitoleic acid, was associated with lower prostate cancer-specific mortality among prostate cancer patients. Citation Format: Meng Yang, Stacey A. Kenfield, Hannia Campos, Howard D. Sesso, Jing Ma, Meir J. Stampfer, Jorge E. Chavarro. Circulating cis- and trans- palmitoleic acid in relation to prostate cancer-specific mortality among prostate cancer patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1871. doi:10.1158/1538-7445.AM2015-1871