Comparative gene and protein expression in primary cultures of epithelial cells from benign prostatic hyperplasia and prostate cancer.

Primary cultures are widely used to investigate the disease-specific biology of prostate cancer and benign prostatic hyperplasia (BPH). To identify genes differentially expressed between epithelial cells cultured from adenocarcinomas versus BPH tissues, we used probe array technology. Gene expression profiles were evaluated on Affymetrix Human Cancer G110 Array Chips containing approximately 1900 cancer-related genes. After defined statistical analysis, genes that were over-expressed in cancer cultures were identified. Protein expression of four of the differentially expressed genes was measured in immunoblots, and the expression of two other genes was measured by real-time reverse transcription-polymerase chain reaction (RT-PCR). While no gene or protein was consistently over-expressed in all cancer versus BPH cell cultures, cytokeratin 16 protein was highly elevated in several of the cancer cultures, suggesting that a hyperproliferative phenotype may be characteristic of prostate cancer cells.

The prostate specific antigen era in the United States is over for prostate cancer: what happened in the last 20 years?

PURPOSE: We assessed how well preoperative serum prostate specific antigen (PSA) reflects the largest cancer in consecutive untreated radical prostatectomies during the last 20 years at Stanford University. MATERIALS AND METHODS: A total of 1,317 consecutive radical prostatectomies were divided into 4, 5-year periods between August 1983 and July 2003, and examined sequentially in 3 mm step sections by 1 pathologist. The largest cancer and 5 other histological variables in each prostate were measured. Preoperative clinical stages were tabulated for each 5-year period. Means, Pearson correlation coefficients, % change and multiple regression were used to compare selected variables. RESULTS: Most parameters decreased linearly during the 20 years, including palpable nodules on digital rectal examination from 91% to 17%, mean age from 64 to 59 years, mean serum PSA from 25 to 8 ng/ml, and index (largest) cancer volume from 5.3 to 2.4 cc. Percent Gleason grade 4/5 of the largest cancer averaged 27% to 35% and prostate weight 44 to 53 gm. Contrasting August 1983 to December 1988 with January 1999 to July 2003, 6 histological cancer parameters had statistically significant relationships to serum PSA in the first period. In the last 5 years serum PSA was related only to prostate size. CONCLUSIONS: Serum PSA was related to prostate cancer 20 years ago. In the last 5 years serum PSA has only been related to benign prostatic hyperplasia. There is an urgent need for serum markers that reflect the size and grade of this ubiquitous cancer.

Genetic profiling of Gleason grade 4/5 prostate cancer: which is the best prostatic control tissue?

PURPOSE: We examined the variation in gene expression profiles of prostate cancer caused by zone specific genes. MATERIALS AND METHODS: Ten normal central zone, 10 transition zone (benign prostatic hyperplasia) and 6 normal peripheral zone tissues from radical retropubic prostatectomies were compared to each other and to 12 peripheral zone Gleason grade 4/5 cancers. Test chips and HuGeneFL6800 (Affymetrix, Inc., Santa Clara, California) chips were used to assay the transcribed genes. Data were obtained with the Microarray Suite Version 4.0.1 (Affymetrix, Inc.) and analyzed statistically. RESULTS: Substantially different gene expression profiles were found depending upon which of the 3 zonal tissues were used as a control. All 3 profiles were compared for efficiency (ability to locate genes) and for robustness (the magnitude of difference between the control and the Gleason grade 4/5 tissue). Microscopically normal appearing peripheral zone tissue at the gene level shows many characteristics of Gleason grade 4/5 cancer. CONCLUSIONS: Gene expression profiles of prostate cancer are affected by the zonal location of the control tissue and the cancer.

Hepsin and maspin are inversely expressed in laser capture microdissectioned prostate cancer.

PURPOSE: Recent studies have shown that hepsin, a serine protease, is over expressed in prostate cancers, implicating hepsin activity in tumor invasion. Using microarray technology we have previously identified 22 genes that were up-regulated in high grade prostate cancers compared with benign prostatic hyperplasia. Of them hepsin was the most differentially over expressed. In the current report we compare hepsin to maspin (BD Transduction Laboratories, San Diego, California), a serine protease inhibitor (serpin), to measure the balance between levels of serine proteases and serpins, which are considered to be a critical determinant of net proteolytic activity. MATERIALS AND METHODS: We combined the technique of laser capture microdissection with gene expression monitoring by micro-array analysis to investigate the gene expression profiles of prostate cells of different histological types. We also studied maspin immunohistochemically. RESULTS: We observed that hepsin as well as 7 of 22 previously reported up-regulated genes demonstrated a pattern of increasing expression with increasing malignant phenotype. In contrast, the expression of maspin (a serpin) decreased with increasing malignancy of prostate cancers. Using immunohistochemistry we observed that maspin protein is expressed strongly in benign prostatic tissues and slightly in grade 3 prostate cancers, and is absent in grade 4/5 cancers. CONCLUSIONS: We conclude that the increased ratio of hepsin-to-maspin may have an important role in prostate cancer progression and invasion.