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)

We have developed a highly sensitive method to detect pelvic lymph node(LN) metastasis using reverse transcriptase-polymerase chain reaction(RT-PCR) with the primers specific for prostate-specific antigen(PSA) gene in combination with the fine needle aspiration biopsy(FNAB). The specimens were obtained from pelvic LN from 15 prostate cancer patients and 15 bladder cancer patients. The aspirated samples (0.05 approximately 0.1 ml) were used for detecting the fragment of PSA mRNA by RT-PCR and Southern blot analysis, and the rest of samples were submitted to conventional cytology. Expression of PSA gene was detected in 9 cases of FNAB samples including all 5 cytologically positive and further more 2 cytologically class III cases, and 2 of 8 cytologically negative cases. RT-PCR of FNAB samples from all cases of bladder cancer were negative for the detection of PSA gene. The sensitivity of PSA gene by RT-PCR was very high and could detect 10 degrees cancer cell. In conclusion, our study suggested that RT-PCR for detection of PSA gene in FNAB samples might become a new diagnostic tool for detection of small foci of prostatic cancer metastasis in LN and combination use of RT-PCR and cytology could greatly contribute to accuracy in diagnosis.
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PMID:[Genetic diagnosis of pelvic lymph node metastasis in prostate cancer using aspiration biopsy samples]. 899 Sep 38

The most efficient strategy for chemoprevention clinical trials are short-term studies which focus on surrogate endpoint biomarkers (SEBs) in high-risk target populations. High-grade prostatic intraepithelial neoplasia (PIN) is the most likely precursor of prostate cancer, and is found in a significant number of routine contemporary needle biopsies without cancer. The frequency and extent of PIN are decreased with androgen deprivation therapy, suggesting that it is a suitable endpoint biomarker for modulation. Potential SEBs for screening chemopreventive agents for prostate cancer in short-term Phase II trials include (1) histologic premalignant lesions, such as high-grade PIN; (2) biochemical markers, including prostate-specific antigen (PSA) serum concentration; and (3) morphometric markers, including nuclear texture, shape, and roundness; size and number of nucleoli; and number of apoptotic bodies; (4) proliferation markers, including MIB-1 and PCNA; (5) genetic markers, including nuclear DNA content (ploidy), oncogene c-erbB-2 (HER-2/neu) expression, fluorescence in situ hybridization for chromosome 8; and PSA-producing cells in the blood detected by reverse transcriptase polymerase chain reaction; and (6) differentiation markers, such as microvessel density as a determinant of angiogenesis. Each of these endpoint biomarkers is measured easily and accurately in serum or in tissue specimens such as formalin-fixed, paraffin-embedded needle biopsies, and may be modifiable by intervention. The clinical utility of these biomarkers as modulatable endpoints in prostate cancer chemoprevention needs to be demonstrated in future clinical trials.
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PMID:Prostatic intraepithelial neoplasia (PIN) and other prostatic lesions as risk factors and surrogate endpoints for cancer chemoprevention trials. 902 13

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 possibility of improving diagnosis of micrometastases from prostate cancer by further enhancing the detection of prostate-specific antigen-producing cells in circulation is being evaluated. We have developed a reverse transcriptase-PCR protocol with the desirable characteristics of low limit of detection, high specificity, reproducibility of response, and ease of performance. Among the procedural alterations that have contributed to these improvements are longer PCR primers, a two-step amplification cycle, and hot-start PCR. We have lowered the limit of detection to one LNCaP prostate-cancer cell in 10(8) peripheral blood mononuclear cells, and samples of blood and bone marrow from healthy donors have yielded no false positives. Because PCR procedures frequently exhibit tube-to-tube variability, we have incorporated a set of internal and external controls into the protocol-a significant advance in assuring assay reliability.
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PMID:Improved reverse transcriptase-polymerase chain reaction protocol with exogenous internal competitive control for prostate-specific antigen mRNA in blood and bone marrow. 906 87

An extremely rare case of esophageal metastasis from prostate cancer is reported. A 65-year-old man presented with anorexia and back pain. Upper gastrointestinal X-ray fluoroscopy and endoscopy revealed a shallow longitudinal ulcer, with converging mucosal folds, approximately 5 cm above the esophagogastric junction. The histological diagnosis of the biopsied specimen was adenocarcinoma. Blood biochemistry revealed elevated serum prostate-specific antigen (PSA) and gamma-seminoprotein levels. Ultrasonography of the prostate disclosed a hypoechoic lesion in the left lobe, and needle biopsy led to the diagnosis of prostatic adenocarcinoma. Since there was no finding suggestive of a primary lesion, apart from that in the prostate, we conducted reverse transcriptase-polymerase chain reaction (RT-PCR) for PSA. PSA-positive mRNA was demonstrated in the tissue of the esophageal tumor. There are three reports on metastasis to the esophagus from prostate cancer, but this is the first case of esophageal metastasis from prostate cancer without any evidence of metastasis to other organs. The importance of RT-PCR for the diagnosis of primary lesions of metastatic cancer is discussed.
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PMID:Esophageal metastasis from prostate cancer: diagnostic use of reverse transcriptase-polymerase chain reaction for prostate-specific antigen. 908 74

Prostate secretory protein of 94 amino acids (PSP94) has shown the potential to be a diagnostic biomarker and a therapeutic agent for prostate cancer. Primates have been the main animal models for studying the biology of this molecule. We have cloned and analyzed the cDNA and promoter region of PSP94 from baboon (Papio anubis). Sequence divergence among baboon, monkey, pig, and human, in both the exons and 5'-flanking region indicates rapid evolution of the PSP94 gene. There are conserved steroid hormone response elements (SHRE) in the promoter region of all three primate species. Multiple, alternative transcripts starting near these SHREs and upstream to the TATA box were identified by reverse transcriptase polymerase chain reaction (RT-PCR) and rapid amplification of 5'-cDNA ends (5' RACE) in primate prostatic tissues. This differential transcription initiation may be linked to androgen regulation of PSP94 gene expression. PSP94 transcripts were detected by RT-PCR in a wide variety of mucus-secreting tissues. However, the alternative transcripts were found only in the prostate. The distribution of the PSP94 protein in baboon secretory tissues was also examined by Western blot analysis using a polyclonal antibody against the human homolog. A positive immunoreactive band was detected, but it was weak, due probably to epitope divergence between the two species. In all young, healthy primate animals tested, the level of immunoreactive PSP94 in prostate tissues was lower than expected. In addition, RT-PCR combined with Southern blot analysis on prostate tissues in these animals failed to detect the PSP57 mRNA produced by alternative splicing of PSP94 primary transcript. These observations can be explained by the sexual immaturity and incomplete prostate development in these young primates. This explanation was supported by histological examination of their prostate during PSP94 immunohistochemistry.
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PMID:Molecular cloning and gene expression analysis of PSP94 (prostate secretory protein of 94 amino acids) in primates. 917 67

Overexpression of p185erbB2/neu has been detected in many adenocarcinomas, including prostatic cancer. In this study, a nontumorigenic cell line isolated from the rat prostatic epithelium (NbE) transfected with the activated oncogene p185neu-T was used to investigate the role of this oncogene in tumor progression. When clones overexpressing p185neu-T were injected orthotopically (1.5 to 2 x 10(6) cells) into the dorsal-lateral prostates of nude mice, prostatic tumors were detected in all mice injected and metastasis to the skeletal muscle in the rib area in 60-80% of the mice injected. Tumor and metastasis origin was confirmed by reselection with G418 and reverse transcriptase-polymerase chain reaction. Control cell lines produced no prostatic tumors or metastases. Incubation at low density (12500 cells/2 cm2) in serum-free medium revealed that clones overexpressing p185neu-T had a higher rate of [3H]thymidine incorporation than did control clones on 3, 5, and 7 d after plating (P < or = 0.0001) and constitutively overexpressed the 2.6-kb ornithine decarboxylase transcript. Additionally, clones overexpressing p185neu-T demonstrated an increased expression of epidermal growth factor receptor and p180erbB4, as judged by RNA blot analysis. Together these data support the hypothesis that overexpression of p185neu-T fosters tumor progression by several pathways, including induction of the metastatic cascade, increased proliferative capabilities, and increased expression of other members of the erbB2 gene family.
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PMID:Metastasis induced by overexpression of p185neu-T after orthotopic injection into a prostatic epithelial cell line (NbE). 925 83

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

When used alone, prostate-specific antigen (PSA) is not sufficiently sensitive or specific to consider it an ideal tool for the early detection or staging of prostate cancer. To optimize the use of PSA, the concepts of PSA velocity, PSA density, and age-related PSA values were developed. Although PSA velocity provides excellent results, its determination requires three PSA values over a 2-year period. The value of PSA density rests on the accurate determination of prostatic volume by transurethral ultrasound (TRUS), which is examiner-dependent. Age-specific reference ranges appear to be more sensitive in men under age 60 than in those over 60. The molecular forms of PSA, especially the percentage of free PSA, seem to be useful tools for the detection of prostate cancer in men with slightly elevated total PSA. New molecular techniques, such as the reverse transcriptase-polymerase chain reaction (RT-PCR), enable the detection of minimal amounts of PSA messenger RNA (mRNA). Human kallikrein 2 (hK2), a serine protease closely related to PSA that also is expressed predominantly in the prostate, may be a new marker for prostate cancer.
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PMID:Prostate-specific antigen: what's new in 1997. 968 75

Oestrogen receptors (ER) and progesterone receptors (PR) have been reported by several authors in the stromal cells of the human prostate. Controversial results exist on the expression of ER and PR in epithelial cells of the prostate. Some recent publications, in contrast to previous findings, have suggested that these receptors are also present in human prostate cancer cell lines derived from metastatic lesions. The expression of ER and PR in these cell lines has been re-examined to determine their presence in lymph node metastases from patients who did not receive any kind of endocrine therapy and in distant metastases obtained from patients who failed endocrine treatment. ER and PR expression in LNCaP, PC-3, and DU-145 cells was assessed by means of the reverse transcriptase-polymerase chain reaction, ligand binding assays, and immunohistochemistry. With all the techniques applied, the three cell lines were found to be negative for both ER and PR. Immunohistochemical analyses were performed in four lymph node metastases obtained at radical prostatectomy from patients who did not receive endocrine therapy and in 17 distant metastases obtained at palliative surgery from patients who failed endocrine therapy. All 21 metastases were negative for ER and PR on immunohistochemistry. These results do not support the recently developed concept that receptors for oestrogenic and progestagenic steroids are present in metastases from human prostate cancer.
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PMID:Metastatic lesions from prostate cancer do not express oestrogen and progesterone receptors. 982 44


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