Dietary Omega-6 and Omega-3 Fatty Acids and Prostate Cancer – Letter

Recently, Aronson and colleagues (1) reported that men with prostate cancer receiving approximately 5 g/d of fish oil combined with a low-fat diet (15% kcal from fat) for 4 to 6 weeks before prostatectomy had 32% lower tumor ki67 staining compared with men consuming a Western diet (45% kcal from fat). This study is of interest because the data suggest that dietary modification can greatly reduce tumor proliferation rates. This article also included results of an in vitro bioassay where sera from subjects pre- and postintervention was used to culture 22RV1 prostate cancer cells and confirmed these findings. This in vitro bioassay has been reported previously by Aronson and colleagues (2, 3) as well as others (4) to provide evidence of chemoprevention. The in vitro bioassay is attractive, given its simplicity and potential for testing how in vivo changes associated with interventions affect cancer cell proliferation. However, to our knowledge, no study has reported the correlations between data from the in vitro bioassay and in vivo cell proliferation from the same individuals. This study provides a platform and opportunity to test the correlation between these 2 assays and determine whether the in vitro bioassay provides a similar depiction of the in vivo environment. Such data would serve as a substantive contribution to the literature, and we hope that the authors will consider publishing such findings.