Fatty acid synthase gene overexpression and copy number gain in prostate adenocarcinoma.

Cancer cells frequently exhibit a significant increase in overexpression and activity of fatty acid synthase (FASN). Elevated FASN pathway activity also occurs in prostate cancer, the second leading cause of cancer-related death in men in the United States. Studies show that genes associated with an increase in protein expression, such as HER2/neu in breast cancer, are associated with an increase in gene copy number as well as an increase in transcription. In the present study, we evaluated whether FASN follows a similar paradigm in prostate cancer. To date, elevated FASN expression in prostate cancer has not been correlated with gene copy number alterations. Using immunohistochemistry and fluorescence in situ hybridization analysis in paraffin-embedded tissue microarrays, we observed gene copy gain in 24% of all prostate adenocarcinoma specimens examined with concurrent increased FASN protein expression. Immunohistochemistry alone showed 59% of prostate cancer specimens in the same tissue microarray with high FASN expression. Increased FASN gene was observed in 53% of all prostate tissues expressing elevated FASN protein levels and in 2 of 5 prostate tumor cell lines tested. These findings suggest that FASN gene copy number increases may be involved in the resultant increase in FASN protein expression observed in prostatic disease.

Androgen regulation of JM-27 is associated with the diseased prostate.

Despite intense research efforts, the etiology of prostatic hyperplasia associated with both benign prostatic hyperplasia (BPH) and prostate cancer remains poorly understood. Our previous studies using array technology identified JM-27 as a transcript that is dramatically up-regulated in the prostates of patients with symptomatic BPH and in normal, adjacent prostatic regions of patients with prostate cancer. In the present study, using an extended sample set, we show a correlation between the messenger RNA and protein expression of JM-27. To investigate the possible functions of this gene, its expression in the rat prostate was examined by immunoblot analysis using a polyclonal antibody specific to human JM-27. This antibody reacts with 2 rat polypeptides of 17 kd and 27 kd in size. Whereas the 27-kd form of the JM-27 protein found in human prostate is selectively expressed in the dorsolateral lobes of the rat prostate, the 17-kd form is expressed only in the ventral lobe. Expression of both forms of this protein appears to be androgen-regulated. There is a time-dependent decrease in expression of the protein products in the ventral and dorsolateral lobes of the rat prostate after castration. Administration of exogenous testosterone in castrated animals maintains protein expression in both lobes. Androgens are believed to play a central role in prostate growth and development, and therefore, it is tempting to speculate that JM-27, an androgen-regulated gene, may be involved in prostatic growth regulation. Further studies are underway to evaluate such a function for JM-27 in prostatic diseases.

Fingerprinting the diseased prostate: associations between BPH and prostate cancer.

Two of the most common diseases which occur in ageing men relate to their prostate. BPH and prostate cancer are prevalent diseases which have an impact on most men as they age. The advent of gene expression analysis has provided an opportunity to examine these diseases in a novel fashion. These analyses, to date, have revealed associations between these two diseases which have not been previously identified. These commonalities include global genetic changes which occur throughout the prostates in individuals with these diseases. Understanding the fingerprints of these diseases is providing novel markers and treatment strategies for both BPH and prostate cancer.