Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.17.21 (prostate-specific membrane antigen)
 1,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report the development of a new sensitive nested reverse transcription-polymerase chain reaction (RT-PCR) assay, using primers derived from the prostate-specific membrane antigen (PSM) cDNA sequence, to detect an hematogenous spread of prostate adenocarcinoma cells. In 60 patients with a biopsy-proven prostate cancer, PSM and PSA RT-PCR detected circulating prostate cells in 40 and 20 patients, respectively. In pT4 M+ and pT3 M+ disease patients, nested PSM primers detected cells in 28 of 33 patients (85%), whereas nested PSA primers detected cells in 17 of 33 (51%). In patients with organ-confined cancer spread (pT2a and pT2b patients) before radical prostatectomy, nested PSM RT-PCR detected circulating prostatic epithelial cells in 6 of 17 patients (35%), which suggests that an hematogenous spread of prostate cells may occur early in prostate cancer history. Altogether, these results suggest that the detection of PSM-expressing cells in blood may predict the development of cancer in patients without clinically apparent prostate cancer. Nevertheless, the potential application and the clinical significance of detection of hematogenous prostate cells through the use of nested PSM primers need an extensive longitudinal study.
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PMID:Enhanced detection of hematogenous circulating prostatic cells in patients with prostate adenocarcinoma by using nested reverse transcription polymerase chain reaction assay based on prostate-specific membrane antigen. 749 5

PSA (prostate specific antigen) and PSMA (prostate specific membrane antigen) serum levels were determined in over 235 prostate cancer patients from 8 different United States clinical urological cancer centers. The clinical data were not known until after the serum assay results were shared with all participants to attempt to eliminate possible clinical bias. PSA values are useful in the clinical diagnosis and staging of prostate cancer patients, and generally fall to low values in response to effective treatment, e.g., surgery, hormones, radiation, chemotherapy. PSMA values are not related to clinical stage but if elevated can fall in response to effective treatments. In contrast, PSMA values can be elevated post-treatment in the presence of very low PSA levels (0.01 to 0.00). The elevated PSMA levels predicted a state of clinical progression or clinical resistance in most cases (> 70%). PSMA levels in this study were of better prognostic value than PSA.
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PMID:Comparison of prostate specific membrane antigen, and prostate specific antigen levels in prostatic cancer patients. 754 69

RT-PCR, if targeted against a prostate-specific marker, can be a highly specific and sensitive assay to detect the presence of occult prostate cancer cells at sites far distant from the primary tumor. The low false-positive rate (0.8%) observed when combining most published studies and the high rate of detection of prostate cells in metastatic patients (88%) found in well-defined clinical studies address the basic requirements of a clinically effective diagnostic modality. Additionally, all reports indicate that RT-PCR positivity for PSA or PSMA increases with increased stage of prostate cancer, suggesting that RT-PCR assays may have value in staging the patient presumed to have clinically localized disease. Indeed, data from two institutions have shown the unique contribution that RT-PCR technology might lend to this most vexing problem. With the suggestive data already published, we remain optimistic that molecular staging will become a reality in the future. After all, the variability in techniques of RT-PCR (as well as differences in targets and samples assayed) used by the various laboratories now investigating this method could themselves be responsible for many of the differences reported. There is no question that standardization among laboratories is essential before clinical utility of molecular staging can be proved. Indeed, this endeavor represents the major aim of the RT-PCR consortium in the United States. Nevertheless, at our own medical center, we are struck by our finding that if a preoperative RT-PCR for PSA is negative, the patient can be assured of a successful operative outcome in 88% of cases. We also are impressed by the data showing that if the serum PSA level is greater than 10 ng/mL and the RT-PCR assay is positive, 90% of patients undergoing radical surgery have adverse pathology reports (and, in fact, have already experience operative failure in nearly half the cases). There is increasing consensus that RT-PCR assays afford prognostic information that is also unique. Three institutions have similar data comparing operative or preoperative RT-PCR strategies (employing all three potential sample sources) with treatment outcome. This may suggest the validity of RT-PCR as a staging modality or, alternatively, suggest that a truly metastatic phenotype is identified in patients with circulating PSA-synthesizing cells, or in patients harboring PSA-synthesizing cells in node or marrow tissues. In either case, RT-PCR appears already to provide information not available before the use of this technology. In fact, in the only series comparing RT-PCR with other, more established predictors (PSA, Gleason score) in a multivariate analysis, RT-PCR status provided the best prognostic information. Prostate manipulation does, in fact, appear to affect the RT-PCR assay. Although digital rectal examination and cystoscopy do not seem sufficiently invasive to release prostate cells into the circulation, a small number of individuals undergoing transrectal ultrasound biopsy will experience this phenomenon. This observation provides a cautionary note relative to timing of sample collection for RT-PCR assays. Furthermore, a significant fraction of patients undergoing prostate manipulation during radical surgery may experience shedding of prostate cells into the operative field and release of some into the peripheral circulation. This has not been universally observed and, even if true, may not share the significance of spontaneous RT-PCR positivity (before prostatic manipulation). In the one instance, a potentially metastatic phenotype is responsible for RT-PCR positivity, whereas in the other instance, PSA or PSMA synthesizing cells may have no metastatic potential at all. Further studies on the biologic half-life of such cells are required before any clinical judgement can be made regarding this phenomenon. In summary, there appears to be consensus that RT-PCR technology can differentiate controls from patients with metas
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PMID:Reverse transcriptase-polymerase chain reaction assays for prostate cancer. 912 34

The immunotherapy of cancer, based on eliciting or enhancing the body's own capacity to mount an effective antitumor response, has produced encouraging early results in the areas of melanoma and renal-cell carcinoma. Such treatments utilizing dendritic cells (DC), immune cells that are excellent antigen presenters, are especially promising. We performed a phase I clinical trial assessing the administration of autologous DC pulsed with HLA-A0201-specific prostate-specific membrane antigen (PSMA) for the treatment of 51 men with hormone-refractory prostate cancer. Participants were divided into five groups receiving four or five infusions of peptides alone (PSM-P1 or PSM-P2; group 1 and 2, respectively), autologous DC (group 3), or DC pulsed with PSM-P1 or P2 (group 4 and 5, respectively). No significant toxicity was observed. Immune reactivity against PSM-P2 was detected in HLA-A2+ patients infused with DC pulsed with PSM-P1 or -P2 (group 4 and 5). An average decrease in PSA was observed only in group 5. Seven partial responders were identified based on NPCP criteria + PSA. The excellent tolerance of this treatment approach, as well as the enhanced cellular responses, decreased PSA levels, and partial clinical responses in some patients suggests that it holds great potential in prostate cancer therapy.
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PMID:Dendritic cell-based immunotherapy of prostate cancer. 941 53

Despite the improvement current evaluation techniques, approximately 30% of prostatic cancers clinically localized to the gland are understaged. RT-PCR is a sensitive and specific screening method for circulating prostatic cells, proposed as a molecular staging tool. The results obtained with this method and reported in the literature are critically discussed. These results, concerning the detection of circulating PSA- or PSMA-positive prostatic cells, are only indicative, as none of the teams used the same method. No consensus has been reached concerning the equipment used, the choice of oligonucleotide primers, the number of cycles to be applied or even the type of method, classical or "nested". Another possible application of this method is early detection of circulating prostatic cells, possibly neoplastic, during the follow-up of patients treated by radical prostatectomy. Once again, the results of the literature are contradictory. The reliability and reproducibility of molecular biology techniques in routine practice must therefore be demonstrated before these techniques can influence the therapeutic decision concerning prostatic cancer.
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PMID:[Molecular staging of prostatic cancer]. 949 Jan 36

Prostate cancer is the most common cancer and the second leading cause of cancer-related death among men. New prostatic markers are needed to increase diagnostic and prognostic effectiveness. One such new marker is prostate-specific membrane antigen (PSMA). PSMA is a highly prostate-restricted membrane glycoprotein that is expressed in normal prostatic epithelial cells and elevated in prostate cancers, especially in poorly differentiated, metastatic, and hormone refractory carcinomas. It has been measured in serum with immunocompetitive and Western blot assays, and its levels have been found to be correlated with the prediction of treatment failure and disease prognosis. Reverse transcriptase-polymerase chain reaction (RT-PCR) assays with primers specific for PSMA have been shown to be more effective than PSA-specific primers in detecting hematogenous circulating prostate cancer cells; however, no clear benefit in patient staging or utility as a predictor of clinical outcome or response to treatment has so far been obtained using RT-PCR methods. PSMA is currently utilized as an immunoscintigraphic target using the antibody conjugate CYT-356 (ProstaScint; Cytogen, Princeton, NJ) and has been shown to have clinical value, particularly in detecting occult prostate cancer. Another current application of PSMA is in immunotherapy of prostate cancer, in which promising results have been obtained in a phase I trial, and a phase II trial is underway. The research summarized in this article indicates that PSMA is an excellent target for diagnostic and therapeutic applications in prostate cancer.
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PMID:Prostate-specific membrane antigen: current and future utility. 950 77

Although adenocarcinoma of the prostate is recently becoming one of most common malignancies in Japanese men, it still poses many questions regarding its etiology, pathology, pathogenesis and clinical management. Many reports have been made on oncogene and tumor suppressor gene, however, frequent genetic alterations have not been identified during prostate cancer development. Loss of heterozygosity (LOH) on 8p might be an important event in the early stage of prostatic carcinogenesis, whereas alteration in 17p is now considered a late event. Numerous reports about the androgen receptor (AR) gene have revealed that mutations in the coding region of AR possibly results in an acquired resistance to androgen blockade therapy and anti-androgen withdrawal syndrome. It has been also shown that shorter CAG repeats of AR gene are associated with a higher risk of prostate cancer. Regarding molecular diagnosis, prostate-specific membrane antigen (PSM) appears to be a new molecule with many potentially valuable applications. PSM-reverse transcriptase-polymerase chain reaction (RT-PCR) is probably more sensitive and specific than PSA-RT-PCR to predict micrometastatic disease. Gene therapy based on the above molecular aspect is currently under investigation but not generally used yet.
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PMID:[Molecular biological aspect]. 961 16

Epithelial cell differentiation is tightly controlled by distinct sets of transcription factors that regulate the expression of stage-specific genes. We recently isolated the first epithelium-specific Ets transcription factor (ESE-1). Here we describe the characterization of ESE-2, a second epithelium-restricted ESE-1-related Ets factor. Like ESE-1, ESE-2 is induced during keratinocyte differentiation. However, whereas ESE-1 is expressed in the majority of epithelial cell types, ESE-2 expression is restricted to differentiated keratinocytes and glandular epithelium such as salivary gland, prostate, mammary gland, and kidney. In contrast to ESE-1, full-length ESE-2 binds poorly to DNA due to the presence of a negative regulatory domain at the amino terminus. Furthermore, although ESE-1 and the amino-terminally deleted ESE-2 bind with similar affinity to the canonical E74 Ets site, ESE-2 and ESE-1 differ strikingly in their relative affinity toward binding sites in the c-MET and PSMA promoters. Similarly, ESE-1 and ESE-2 drastically differ in their ability to transactivate epithelium-specific promoters. Thus, ESE-2, but not ESE-1, transactivates the parotid gland-specific PSP promoter and the prostate-specific PSA promoter. In contrast, ESE-1 transactivates the keratinocyte-specific SPRR2A promoter Ets site and the prostate-specific PSMA promoter significantly better than ESE-2. Our results demonstrate the existence of a unique class of related epithelium-specific Ets factors with distinct functions in epithelial cell gene regulation.
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PMID:Characterization of ESE-2, a novel ESE-1-related Ets transcription factor that is restricted to glandular epithelium and differentiated keratinocytes. 1050 7

BACKGROUND: Molecular techniques have been developed recently to assess for circulating tumor cells. This "molecular staging" of prostate cancer uses the reverse transcription-polymerase chain reaction (RT-PCR) to detect cells that contain PSA or PSMA in the bloodstream. Currently, the clinical application of this concept is controversial. METHODS: The authors discuss the current status of molecular biologic methods to detect circulating prostate cancer cells. They report on the limitations of the technology and the advances that will allow the quantification of these circulating cells. RESULTS: Studies generally indicate an increasing level of PSA RT-PCR positivity as disease advances. However, reports have been significantly diverse, and there is no clear explanation for this disparity. CONCLUSIONS: The determination of the "circulating prostate cancer cell load" by RT-PCR or other techniques may prove to be useful in the management of patients with prostate cancer, but questions remain to be answered before we can develop and assess new therapeutic strategies that will advance the treatment of prostate cancer before metastasis becomes evident. A better understanding of the biology of tumor cells present in the circulatory system is also needed.
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PMID:Circulating Prostate Cancer Cells Detected by Reverse Transcription-Polymerase Chain Reaction (RT-PCR): What Do They Mean? 1076 Oct 99

Serummarkers for prostate carcinoma are widely applied for the purpose of early detection of cancer and the differentiation between benign and malignant disease, for the pre-treatment staging of detected prostatic cancers, and for the monitoring of prostate cancer after curative or palliative therapies. This review illustrates the limitations of current markers for prostatic disease in blood en serum. It gives an overview of what is known about PSA and its isoforms, hK2, PSMA, and PSCA, and discusses, based on this information, in what direction current research is developing in order to improve these markers.
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PMID:Blood and serum substances for markers of prostate cancer. 1107 13


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