| Prostate cancer is common malignant tumor in older male genitourinary system and is the second leading cause of cancer-specific death after lung cancer and its incidence rate is in the first place among men in the United States. Prostate is localized in secluding locus, so prostate carcinoma frequently occurred in peripheral zone that is far away urethra. Because prostate cancer have not specific clinical symptoms, prostate cancer patients who are diagnosed by clinical doctors most have presented bone and lung metastasis and have lost the opportunity of radical prostatectomy(RP). Since prostate specific antigen (PSA) is regarded as a useful serum marker for prostate cancer screening in population, it has undergone significant change of prostate cancer diagnosis. Prostate cancer screening by using PSA in population has been firstly practiced in the United States. Especially it has been performed all over in U.S.A from 1989, it has indeed realized prostate cancer early diagnosis and therapy. In China during the last score years, with the changing of life-behaviour and diet habit, the increasing of aged men, and the developing of diagnose level, the incidence of prostate cancer are increased rapidly. Metastasis is the important character of malignant tumor and is the main cause of recurrence after radical prostatectomy and of radiotherapy and chemotherapy failure, meanwhile, it is also the main factor to limit cure rate enhance of the tumor patients. The detection of tumor metastasis focus in lymph node, peripheral blood and bone marrow may provide guided value of judging the tumor diagnose, clinical stage, recurrence after radical prostatectomy and prognosis and of therapy. Then, what is micrometastasis? It is that the malignant tumor cells disseminated and existed in blood circulation,lymphatic system,bone marrow and other organs during the developing program, neither metastasis nod nor clinical symptom could be found. It is that the malignant tumor metastasis excepted blood system tumor could not be detected by conventional methods, such as screenage and pathology methods. The number of micrometastasis tumor cells is very small, so these cells are not easily detected by using conventional methods, such as HE staining, continuous section, immunohistochemistry, tissue culture, etc. Reverse transcriptase polymerase chain reaction is regarded as the most prevalent method to detect micrometastasis because of its sensitivity extremely, specificity sufficiently and operation simply and quickly. The detection of circulating tumor cells (CTC) has been paid attention to by researchers and physicians since 1869 when Ashworth described a case of cancer in which cells similar to those in the tumor were found in the periphery blood after death. In the last decade year, many institutions have attempted to detect solid tumor cells in periphery blood using extremely sensitive RT-PCR, these assay were in the vast majority directed against tissue-specific markers. In the present studies, it has been shown that RT-PCR technique is superior to conventional techniques in detecting circulating tumor cells. RT-PCR allows the identification of one tumor cell mixed in 107～108 normal cells, so it is a powerful and highly sensitive tool that it has the ability to detect small numbers of prostate cells disseminated within the periphery blood or within other body fluids or tissues and it has a significant predictive value of tumor micrometastasis. Prostate-specific antigen (PSA) is a single-chain glycoprotein, secreted by prostate epithelia cells, and is a human kallikrein family member, and has chymotrypsin-like enzymatic activity. Usually, PSA mRNA expresses specifically in prostate tissue, but it should not express in normal circulating blood, bonemarrow and lymph node. If PSA mRNA has been detected in above-mentioned tissues, we may believe that there are prostate cancer cells in those tissues and that there are metastasis foci in the body. Because of the indispensable role of PSA in prostate cancer diagnosis, we chose PSA as specific tumor marker in our study. Additionally, the detection of PSA gene expression in transcription level and translation level can be performed by combining RT-PCR with Western blot, which can judge prostate cancer micrometastasis precisely. Objection:To detect the prostate cancer patients and the control's expression of the PSA mRNA and protein in mononuclear of the peripheral blood and discuss the relationship between positive expression of two parameters and prostate cancer micrometastasis. Methods:39 patients who had prostate cancer detected were selected, in which whose serum PSA are more than 40.0ng/ml were 23 cases, whose distribution in different clinical stage was B stage 0 case, C stage 5 cases and D stage 18 cases and whose distribution in different Gleason Score was 2～6 score 10 cases, 7～10 score 13 cases. And patients whose serum PSA are less than 20.0ng/ml were16 cases, whose distribution in different clinical stage was B stage 6 cases, C stage 9 cases and D stage 1 case and whose distribution in different Gleason Score was 2～6 score 9 cases, 7～10 score 7 cases. While there was none case whose serum PSA is between 20.0～40.0ng/ml, so this group had been gated out. 12 men who are health were selected as normal control group. 5 ml anticoagulant blood was collected in every individual. The expression of the PSA mRNA and protein in the mononuclear of the peripheral blood were detected by combining RT-PCR with Western blot after delamination of the mononuclear cells. Results: (1) There were 23 patients whose serum PSA are more than 40.0ng/ml,and positivity rate of PSA mRNA and protein was 86.96% and 86.96% respectively, the number of positive expression of the two methods were 19, the positivity coincidence rate was 82.61%; there were 16 patients whose serum PSA are less than 20.0ng/ml, and positivity rate of PSA mRNA and protein was 37.5% and 37.5% respectively, the number of positive expression of the two methods were 5, the positivity coincidence rate was 31.25%. In contrast, the expression of PSA mRNA and protein in control group was negative. (2) The positive expression of PSA mRNA and protein was positive correlated clinical stage, r=0.701, p<0.01, r=0.325, p<0.05 respectively; and the positive expression of PSA mRNA and protein was positive correlated Gleason score, r=0.614, p<0.01, r=0.472, p<0.05 respectively by using Pearson correlation analysis. (3) The patients whose serum PSA are more than 40.0ng/ml, the positive rate of PSA mRNA and protein was 80% , 80% respectively in Gleason score 2～6 region and was 92.3% ,92.3% respectively in Gleason score 7～10 region. While patients whose serum PSA are less than 20.0ng/ml,the positive rate of PSA mRNA and protein was 0% ,11.11% respectively in Gleason score 2～6 region and was 85.71% , 71.43% respectively in Gleason score 7～10 region. (4) The patients whose serum PSA was less than 20.0ng/ml were followed-up 18 months, and there was 1 patient had died of prostate cancer metastasis within 6 months after radical prostatectomy(RP) among 5 patients whose PSA mRNA were positive expression as well as protein. In contrast, those whose PSA mRNA and protein were negative expression hadn't presented metastasis. Conclusions: (1) There are high positivity rate, high coincidence rate and sufficient sensitivity of the expression of PSA mRNA and protein in mononuclear cells of the peripheral blood among the patients whose serum PSA are more than... |
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