| ObjectiveProstate carcinoma is the most frequent cancer in males in western countries. As the age indication increases and the dietary ingredient changes in China, the incidence and death rate of prostate cancer raises gradually in the past decades. Although previous studies revealed that prostate cancer progression is a process involving multiple molecular alterations, the precise molecular mechanisms of prostate cancer remain poorly understood. On the other hand, benign prostatic hyperplasia (BPH) is the most common benign disease of prostate, both diseases involve overgrowth of the epithelial cells. Whereas cancerous growth of the epithelial cells is characterized by accumulation of molecular abnormalities because of genomic instability, BPH represents the overgrowth with rare genetic abnormalities. Therefore, comparative analysis of gene expression in prostate cancer and BPH specimens may provide important information relating (o malignant transformation of prostatic cells. Now serum PSA is widely used as a diagnostic marker for prostate cancer, but the level below 10 ug/ml is hard to predict the presence of prostate cancer. Thus there is an urgent need for identifying new prostate cancer markers. The gene therapy for prostate cancer need the ideal therapeutic targets too. Recently the emerging technology of DNA microarray provide a powerful tool to investigate the gene expression profile ofthousands of genes in prostate cancer. To further understand of the molecular mechanisms of prostate cancer development and progression, we used the technology of microarray to investigate the genes differentially expressed in prostate cancer and to determine some prostate cancer associated genes for diagnosis and treatment prostate cancer. Methods:oligonucleotide microarray, which contained probe sets for 458 known human genes and 7 housekeeping genes, were made to investigate the gene expression profile of prostate cancer and BPH. Firstly Total RNA was isolated from the tissues of prostate cancer and BPH, then synthesis and labeling of cDNA were achieved by direct incoporation of Cy3-dUTP in a reverse transcription reaction using Total RNA, the Cy3-labeled cDNA of prostate cancer and BPH was respectively hybridizated to a microarray. Finally the hybridized slides were scanned with ScanArray Express scanner and scanned image files were analyzed with QuantArray software. We removed the genes that were undetectable in all samples. Statistical analysis was performed using two-tailed / test. Only up and down-regulated genes with a significant difference (/*<().05) in fluorescence between prostate cancer and BPH were selected. Then we selected the genes exhibiting a >2-fold expression change in prostate cancer samples relative to BPH samples and ranked them in terms of their over and down-expression. Microarray data for overexpressed gene P1M-1 was confirmed by reverse transcription polymerase chain reaction (RT-PCR). We further investigated PIM-1 and c-Myc protein expression in malignant and benign prostate samples by immunohistochemical analysis.Results:1. The results of microarray and RT-PCR show a high correlation, which imply the microarray data were reliable.2. A total of 35 genes differentially expressed with prostate cancer and BPH was screened out, of which 17 genes were up-regulated and 18 genes were down-regulated in prostate cancer. The 35 genes can be divided into 6 functional categories, which include the genes of growth factor, cytokine, oncogene and tumor suppressor gene. The largest category is the genes of growth factor and the receptor. 6 differentially expressed genes locate in chromosome 1. 4 genes were found to involve in extracellular matrix (ECM) degradation. We firstly identified FZD5 was overexpressed in prostate cancer.3. The protein expression levels of PIM-1 in prostate cancer were higher than these in BPH and high-grade prostatic intraepithelial neoplasia (HG-PIN) (P<0.001, P<0.05). The expression levels of PIM-1 in HGPIN was higher than these in BPH too (PO.01). The expression of PIM-1 was related significantly to the histologic grade and clinical stage of prostate cancer. The expression of PIM-1 in prostate cancer with lymph node metastasis were higher than these without lymph node metastasis (PO.05), but the expression levels of PIM-1 in prostate cancer with and without surgical margin metastasis were no significant difference (7^-0.05). There were no significant relationship between PIM-1 expression and serum PSA and age of patients was found. The protein expression levels of c-Myc in prostate cancer and HGPIN were higher than these in BPH (/'<0.001, /><0.05). Thefexpression of c-Myc in prostate cancer and HGPIN were no significant...
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