Candidate genes involved in enhanced growth of human prostate cancer under high fat feeding identified by microarray analysis

BACKGROUND Several studies have suggested that a high fat diet (HFD) may be a risk factor of prostate cancer (PCa). As a first step to delineate the molecular mechanisms underlying the enhanced progression of PCa under HFD, we investigated the differential gene expressions of a human PCa xenograft under HFD and a low fat diet (LFD). METHODS LNCaP cells were subcutaneously injected in 20 nude mice, which were equally divided into two groups, the HFD group and LFD group. Oligonucleotide microarray analyses were performed using mice xenografts from HFD and LFD, and the results of candidate genes with a significant differential expression were validated by quantitative RT‐PCR experiments. As for insulin‐like growth factor I receptor (IGF‐IR), protein expression levels were further examined by immunohistochemistry in xenograft tissues and in 78 radical prostatectomy specimens. RESULTS Tumor volume and serum PSA levels were significantly higher in the HFD group than in the LFD group (P