Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

While not all circulating tumor cells survive, one could postulate that patients with circulating tumor cells might be candidates for adjuvant chemotherapy because of the risk of relapse. Recently, reverse transcriptase-polymerase chain reaction (RT-PCR) for the detection of circulating tumor cells has been suggested as a potential technique for staging of cancer. In malignant melanoma, the detection of circulating melanoma cells by tyrosinase RT-PCR correlated with the clinical stage of patients and was an independent prognostic factor for recurrence. A strong association was found between the detection of neuroblastoma cells in circulation by tyrosine hydroxylase RT-PCR with bone marrow micrometastasis. This method may be of use to identify early signs of relapse in disease-free patients. In prostatic cancer, the frequency of positivity for detection of circulating tumor cells in peripheral blood by PSA RT-PCR increased with tumor stages but a significant proportion of patients with metastatic disease were negative. The prognostic significance of the detection of tumor cell in blood in other epithelial tumors is not established and will require further long-term follow-up study.
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PMID:[Molecular diagnostic detection of circulating tumor cells and their prognostic implications]. 905 Nov 25

The present study addressed the question as to whether prostate-specific antigen reverse transcriptase-polymerase chain reaction (PSA RT-PCR) could be used to identify prospectively men who have prostate cancer and to help determine which patients with an initially negative biopsy would benefit from rebiopsy. PSA RT-PCR was performed prospectively on 90 patients who were to have a prostate biopsy because of an elevated PSA level, an abnormal digital rectal examination, or both. PSA RT-PCR was performed, and the sensitivity of the test was enhanced by hybridization of the PCR with a 32P-labeled PSA cDNA probe (exons 3-5). Of the 90 men, 36 (40%) had prostate cancer on biopsy. Of these 36 men, 5 (13.9%) had a positive PSA RT-PCR finding, whereas 31 (84.1%) tested negative. Of 54 men with negative biopsies, 8 (14.8%) had a positive PSA RT-PCR result. The sensitivity of PSA RT-PCR for the detection of biopsy-proven prostate cancer was 13.9% and the specificity was 85.2%. Only 3 of 12 (25%) patients with advanced disease had a positive test result. The sensitivity of PSA RT-PCR for the detection of biopsy-proven prostate adenocarcinoma in men suspected of having prostate cancer is poor. Indeed, men without biopsy-proven prostate cancer are just as likely to have a positive result in the PSA RT-PCR as are men with cancer. Whether these men with negative prostate biopsies and positive PSA RT-PCR findings may eventually develop prostate cancer remains to be determined. At this time, PSA RT-PCR for the prospective detection of prostate cancer should be considered investigational.
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PMID:Can prostate-specific antigen reverse transcriptase-polymerase chain reaction be used as a prospective test to diagnose prostate cancer? 928 55

Recent advances in molecular technology have been applied to the detection, staging, and prognosis of prostate cancer. The reverse transcriptase-polymerase chain reaction (RT-PCR) is an exquisitely sensitive tool that allows for the detection of minimal quantities of cells. The assay has been studied clinically to distinguish metastatic prostate cancer patients from controls, and to preoperatively stage prostatic carcinoma; it also has been studied as a marker for postoperative recurrences. We review our experience at Columbia University and reports in the literature from other institutions to date. In addition, we provide our most recent data correlating the "enhanced" RT-PCR for PSA assay of peripheral blood specimens with final pathologic stage in 300 radical prostatectomy patients.
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PMID:The role of reverse transcriptase-polymerase chain reaction for staging patients with clinically localized prostate cancer. 950 82

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

We developed a highly sensitive splice variant-specific reverse transcriptase-PCR (RT-PCR) assay for human glandular kallikrein (hK2) mRNA and tested its ability to detect metastatic disease in men with clinically localized prostate cancer. An RT-PCR assay using primers spanning intron IV and including a significant portion of the 3' untranslated region of the hKLK2 gene, with maximum nonhomology to both hK1 and hK3, was developed. The limit of detection of the assay was five copies of hK2 cDNA and one LNCaP cell in 10(9) lymphoblasts. RT-PCR-hK2 was performed on preoperative peripheral blood specimens from 228 consecutive radical prostatectomy patients as well as 7 metastatic prostate cancer patients and 14 healthy men without prostate cancer. This new RT-PCR-hK2 assay amplifies two distinct fragments. The larger fragment (hK2-U) is approximately 680 bp in length and corresponds to the amplified product of a previously reported splice variant in the splice donor site of intron IV in the hKLK2 gene. The smaller fragment (hK2-L) is approximately 643 bp in length and corresponds to the amplified product of the native hK2 mRNA. Whereas the RT-PCR-hK2-L assay was positive in 71% of our patients with metastatic prostate cancer, 14% of healthy control men also tested positive. By univariate (P = 0.028) and multivariate (P = 0.0269) analysis, which controlled for preoperative PSA, clinical stage, and biopsy Gleason score, RT-PCR-hK2-L status added prognostic information to the prediction of lymph node-positive disease. We have developed a new RT-PCR assay which demonstrates a high sensitivity for detecting hK2 mRNA. Preoperative RT-PCR-hK2-L status helps predict pathological lymph node positivity in patients with clinically localized prostate cancer.
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PMID:Detection of metastatic prostate cancer using a splice variant-specific reverse transcriptase-polymerase chain reaction assay for human glandular kallikrein. 1115 23

A sensitive technique using reverse transcriptase-polymerase chain reaction (RT-PCR) for PSA mRNA has been used to detect circulating tumor cells in the peripheral blood of prostate cancer patients. We evaluated the clinical utility of this method for staging and monitoring for prostate cancer. The number of patients who were RT-PCR positive was increased in higher clinical stages. This technique may provide useful information for treating patients with prostate cancer, especially candidates for radical prostatectomy. Confirming the value of this modality as a prognostic factor will require further study.
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PMID:[Detection of PSA mRNA in prostate cancer patients' blood]. 1176 74

Increasingly, reverse transcriptase polymerase chain reaction (RT-PCR) is used to detect clinically significant tumour cells in blood or bone marrow. This may result in a redefinition of disease-free and clinical relapse. However, its clinical utility may be limited by lack of automation or reproducibility. Recent studies have suggested nucleic acid sequence-based amplification of target RNA may be more robust. In this study, nucleic acid sequence-based amplification was established to detect melanoma, colorectal and prostate cancer cells. Nucleic acid sequence-based amplification and RT-PCR both successfully amplified target RNA in peripheral blood samples from patients with melanoma and colorectal cancer, but only RT-PCR detected PSA in blood samples from patients with prostate cancer. There was relatively good agreement between sample replicates analyzed by RT-PCR (Kappa values of one for tyrosinase, 0.67 for CK-20 and one for PSA), but less agreement when analyzed by nucleic acid sequence-based amplification. This may limit the routine use of NASBA for the detection of clinically significant disease. In summary, RT-PCR appears at present to be the most reliable and reproducible method for the detection of low-level disease in cancer patients, although prospective studies are warranted to assess the clinical utility of different molecular diagnostic methods.
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PMID:Comparison of the RNA-amplification based methods RT-PCR and NASBA for the detection of circulating tumour cells. 1185 20

African-Americans (AAM) with prostate cancer are more likely to relapse than Caucasian-Americans (CAM) despite controlling for known prognostic factors. One explanation may be that micrometastatic disease in AAM behaves more aggressively than in CAM. We tested this hypothesis by comparing the reverse transcriptase polymerase chain reaction amplification of the Prostatic Specific Antigen-mRNA (RTPCR PSA-mRNA) results from peripheral blood samples of AAM and CAM with respect to disease outcome. We evaluated the peripheral blood of 246 consecutive patients at the time of radical prostatectomy. The RTPCR PSA-mRNA test for determination of circulating prostate cancer cells was performed. The results were stratified by races and correlated with standard clinico-pathological variables and disease free survival. 27% and 23% of AAM and CAM patients were RTPCR PSA-mRNA positive, respectively. The RTPCR PSA-mRNA status correlated with the pathologic stage in CAM but not in AAM, (p = 0.05). There was no association with Gleason score, PSA level, or clinical stage with the RTPCR PSA-mRNA status in either group. AAM with organ-confined prostate cancer were marginally more likely to have circulating prostate cells than similarly staged CAM (24% vs. 17%). In AAM but not CAM who had prostate cancer, the RTPCR PSA-mRNA status correlated with and was an independent predictor of disease-free survival. Our data suggests that, though the likelihood of having circulating prostate cells is the same in AAM and CAM, the presence of circulating prostate cells in AAM is predictive of a worse outcome. This may partially explain the worse prognosis in AAM vs. CAM with clinically localized prostate cancer.
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PMID:Presence of circulating prostate cancer cells in African American males adversely affects survival. 1247 30

Orotate phosphoribosyl transferase (OPRT) is the initial enzyme of 5-fluorouracil (5-FU) activation, in which 5-FU is converted to 5-fluorouridinemonophosphate. Dihydropyrimidine dehydrogenase (DPD) is a degrading enzyme that catabolizes 5-FU. In this study, we investigated the expression of these enzymes in normal prostate gland (NP), hormone-sensitive prostate cancer (HSPC) and hormone-refractory prostate cancer (HRPC). Forty-two prostatic tissue specimens were obtained from patients who had undergone prostate needle biopsies without any treatments or with PSA failure after initial androgen deprivation. The tissue samples derived from formalin-fixed, paraffin-embedded sections were made by laser-captured microdissection and from those RNA was extracted. The levels of OPRT and DPD mRNA expression were examined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The level of OPRT mRNA expression in the HSPC or the HRPC specimens was significantly higher than that in the NP specimens. Immunohistochemical staining for OPRT revealed strong expression of OPRT in prostate cancer cells. There was a significant correlation between OPRT mRNA expression levels and the tumor pathological grade. Furthermore, the OPRT/DPD expression ratio, a powerful predictive factor to evaluate 5-FU sensitivity, in the HRPC group was significantly higher than that in the low grade HSPC group. Thus, 5-FU may be an effective option for some HRPC patients.
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PMID:Overexpression of orotate phosphoribosyl transferase in hormone-refractory prostate cancer. 1908 40

A single strain of Bacteroides fragilis synthesizes eight distinct capsular polysaccharides, designated PSA to PSH. These polysaccharides are synthesized by-products encoded by eight separate polysaccharide biosynthesis loci. The genetic architecture of each of these eight loci is similar, including the fact that the first gene of each locus is a paralog of the first gene of each of the other PS loci. These proteins are designated the UpxY family, where x is replaced by a to h, depending upon the polysaccharide locus from which it is produced. Mutational analysis of three separate upxY genes demonstrated that they are necessary and specific for transcription of their respective polysaccharide biosynthesis operon and that they function in trans. Transcriptional reporter constructs, reverse transcriptase PCR, and deletion analysis demonstrated that the UpxYs do not affect initiation of transcription, but rather prevent premature transcriptional termination within the 5' untranslated region between the promoter and the upxY gene. The UpxYs have conserved motifs that are present in NusG and NusG-like proteins. Mutation of two conserved residues within the conserved KOW motif abrogated UpaY activity, further confirming that these proteins belong to the NusG-like (NusG(SP)) family. Alignment of highly similar UpxYs led to the identification of a small region of these proteins predicted to confer specificity for their respective loci. Construction of an upaY-upeY hybrid that produced a protein in which a 17-amino-acid segment of UpaY was changed to that of UpeY altered UpaY's specificity, as it was now able to function in transcriptional antitermination of the PSE biosynthesis operon.
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PMID:A family of transcriptional antitermination factors necessary for synthesis of the capsular polysaccharides of Bacteroides fragilis. 1980 12


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