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)

The presence of circulating tumor cells in bone marrow and peripheral blood of cancer patients may reflect the aggressiveness of the disease. This also applies to cancers that rarely give rise to overt bone marrow metastases. The clinical validity of micrometastasis detection for staging and prognostication depends on the sensitivity and reliability of the detection method. In malignant melanoma, most studies have used reverse transcriptase polymerase chain reaction (RT-PCR) techniques, commonly with tyrosinase mRNA as the target molecule. Unfortunately, highly inconsistent results have been reported, raising doubts about this approach. In a study of 81 melanoma patients with metastatic disease, we used an immunobead rosetting method in which live melanoma cells are selected and identified by binding of paramagnetic beads coated with the 9.2.27 antibody against the high molecular weight melanoma-associated antigen. In bone marrow samples obtained from 60 patients, 14 (23.3%) were positive, compared to only two of 81 in blood. A highly significant correlation (p = 0.0001, log rank test) was found between micrometastasis positivity and overall survival from time of removal of the primary tumor. Moreover, in regression analysis it was found that the presence of micrometastatic cells was an independent and the most important indicator of poor prognosis, with a relative risk of 5.38. The immunomagnetic method is simple, rapid, and highly sensitive and will be used in further prospective clinical studies.
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PMID:Immunobead-based detection and characterization of circulating tumor cells in melanoma patients. 1109 32

The presence of metastatic disease in the regional nodal basin is the most important prognostic indicator for patients with malignant melanoma. The metastatic status of the sentinel lymph node (SLN), defined as the first node in the basin to drain a primary tumor, has been shown to represent that of the entire basin. Since routine histologic examination of lymph nodes often underestimates the presence of micrometastatic disease, a more sensitive assay for detecting tumor cells is needed. We have previously shown that a molecular assay based on the reverse transcriptase polymerase chain reaction (RT-PCR) was able to define a population of patients at higher risk for both recurrence and death, compared with routine H&E histology. Recently, we have compared "molecular staging" of patients by RT-PCR with conventional S-100 immunohistochemistry (IHC) staining of the SLNs. In these studies, SLN specimens were bivaled, and half of each specimen was examined by routine histology, including both H&E and S-100 IHC. The other half of each specimen was analyzed by a nested RT-PCR assay. H&E histology alone detected metastatic disease in 36 of 233 (16%) patients tested. Serial sectioning and IHC detected micrometastatic disease in another 16 patients, thus increasing the proportion of patients with nodal disease to 22%. RT-PCR detected micrometastatic disease in 114 of 181 patients who were negative by conventional methods, further increasing the proportion of patients with evidence of nodal disease to 70% overall. The clinical significance of these findings is still uncertain. The value of additional therapy (including elective lymph node dissection and interferon therapy) for patients who are positive only by the molecular method is currently being investigated by the national multi-center Sunbelt Melanoma Trial.
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PMID:The clinical relevance of molecular staging for melanoma. 1109 46

Detection of breast cancer micrometastases based on specific genetic markers may provide useful information to justify appropriate therapeutic strategies. We examined the presence of a carcinoembryonic antigen (CEA) messenger RNA(mRNA) in the peripheral blood of 32 patients with varying stages of breast cancers by means of the reverse transcriptase-polymerase chain reaction (RT-PCR) assay prior to and after the curative operation. CEA mRNA were detected in the peripheral blood samples from 12 (38%) out of 32 breast cancer patients prior to surgery. Among 12 CEA mRNA-positive patients prior to surgery, 4 (33.3%) relapsed from breast cancer within 2 years after surgery. Moreover, CEA mRNA was detected in the peripheral blood samples obtained prior to surgery in 3 out of 11 patients (27.2%) with a stage I disease. One out of three of these patients had a relapse in lung. There were four patterns of CEA mRNA expression, ( +, + ), (+, -), (-, + ), and (-, -) in the pre- and post-operative blood samples. In 12 CEA mRNA-positive patients submitted to surgical resection of the primary tumor, persistence of CEA mRNA expression was observed in five patients (+, +) within a month after surgical treatment. Three out of these 5 patients (60%) relapsed from breast cancer within 2 years after surgery. In 7 other patients (+, -), CEA mRNA expression was not detected within a month after tumor removal, and recurrence occurred in 1 out of the 7 patients (14%) within 2 years after surgery. In 19 patients, CEA mRNA expression was not detected in pre- or post-operative blood samples (-, -). There was a patient whose blood sample was negative for CEA mRNA before the operation, but changed to show a positive result after surgery (-,+). No recurrence was found in 20 of CEA mRNA-negative patients prior to surgery (-, +), (-, -). This study suggested that the presence of CEA mRNA expression in preoperative peripheral blood sample represent the progression of the disease, especially the risk of hematogenous metastasis in the patients in spite of their clinical stage, and the presence of CEA mRNA in the postoperative blood sample may represent the evidence of a residual disease. Thus consideration might be given for adding combined multi-modal therapy.
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PMID:Clinical significance of circulating cancer cells in peripheral blood detected by reverse transcriptase-polymerase chain reaction in patients with breast cancer. 1131 30

A newborn baby boy was diagnosed with the mixed form of congenital mesoblastic nephroma (CMN) representing both classic and cellular histology features in the renal tumor. Additionally, the patient had skin and bone lesions consistent with multifocal involvement of a generalized infantile fibromatosis (IFS). Both skin and bone lesions were distinctly different from CMN and did not represent metastasis. The primary tumor cell line (MCH-MN-1), established from the resected right kidney tumor, had a diploid DNA content. Cytogenetic studies revealed deletion on the long arm of chromosome 3 (q21q24) and duplication on the short arm of chromosome 11 (p15). MCH-MN-1 cells expressed ETV6-NTRK3 gene fusion transcripts, characteristic of cellular and mixed forms of CMNs. The cells had high p21 and low Bax mRNA expression in the reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The high level of proliferative marker (Ki67) mRNA expression correlated well with the pluripotent nature of MCH-MN-1 in tissue culture (cell doubling time = 12.4 h). Our results showed that MCH-MN-1 might be a good model cell line for investigations on mesoblastic nephroma.
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PMID:Cytogenetic and molecular characterization of a congenital mesoblastic nephroma. 1144 43

The monoclonal antibody Ki-67 and the isospecific monoclonal antibody MIB-1 are routinely used in oncology to assess the proliferation index of tumor cells. A more objective and sensitive method is the determination of the of Ki-67 protein-specific mRNA by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). In 25 resected colorectal adenocarcinomas of different stages and grades we determined between 0.2 and 4.4 amol (10(-18) mol) Ki-67 protein-specific mRNA per microgram total RNA (median = 0.88 amol). The corresponding Ki-67 indices (expressing the percentage of Ki-67/MIB-I positive tumor cells) ranged from 41 to 81% (median = 61%). We found a good correlation between Ki-67 index and mRNA expression (r = 0.75), a significant correlation between both data and tumor stage (primary tumor, regional nodes, metastasis [pTNM] staging classification) (p < 0.001), but not between both data and tumor grade. Both Ki-67 indices (p = 0.05) and mRNA levels (p = 0.014) correlated significantly to the patients' survival. These results demonstrate that the Ki-67 protein-specific quantitative RT-PCR is a useful method for the characterization of tumor cell proliferation.
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PMID:Assessment of proliferative activity in colorectal carcinomas by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). 1148 1

Hemangioma is a primary tumor of microvasculature. Its development typically exhibits a proliferative phase followed by an involuting phase that continues into the involuted phase. Although apoptosis has been reported, the mechanisms regulating the spontaneous regression of hemangioma are largely unknown. The authors recently demonstrated up-regulation of the mitochondrial cytochrome b gene in hemangioma associated with steroid-induced regression. The present study investigated whether a similar change occurred during spontaneous regression. Biopsy material was obtained from 11 patients with hemangiomas at different phases of development. In one of these patients, a biopsy was taken from the proliferative, involuting, and involuted areas of the hemangioma. In another patient, a biopsy was taken before and 5 weeks after the intralesional administration of steroids. From each tissue specimen, RNA was isolated and subjected to reverse transcriptase-polymerase chain reaction analysis by use of specific primers for the human mitochondrial cytochrome b gene. Semiquantitative reverse transcriptase-polymerase chain reaction analysis revealed that the strongest expression of the mitochondrial cytochrome b transcripts was in specimens taken from hemangiomas in the involuting phase compared with those from the proliferative and involuted phases. The authors concluded that mitochondrial cytochrome b is associated with both the spontaneous and the steroid-induced regression of hemangioma, probably by regulating apoptosis.
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PMID:Altered mitochondrial cytochrome b gene expression during the regression of hemangioma. 1171 10

Fas ligand (FasL) is a type II transmembrane tumor necrosis factor family protein, known to trigger apoptosis in cells that bear the FasL receptor, Fas. The authors found that normal prostate, benign hyperplasia, and most prostatic carcinoma cells at the primary site did not express FasL, whereas metastatic prostatic carcinoma cells in lymph nodes and bone marrow displayed almost uniform, immunohistochemically detectable, FasL expression. However, small foci of FasL-positive prostatic carcinoma cells amid a vast majority of FasL-negative tumor cells were noted at the primary sites in patients with distant metastases. Analysis of the FasL gene and its mRNA by polymerase chain reaction and reverse transcriptase-polymerase chain reaction, respectively, suggested that the expression of immunohistochemically detectable FasL in metastatic tumor cells was not due to mutation in the FasL gene with resulting overexpression. Further, FasL expression was detectable in the acinar epithelial cells of prostates with morphologic atrophic changes, suggesting that FasL also plays a role in the physiologic apoptosis process of noncancerous prostate. The current data suggest that a subpopulation of prostate carcinoma cells clonally expresses FasL, and this subpopulation may have metastatic potential. Evaluation of FasL expression in the primary tumor thus may provide a useful parameter for predicting metastatic potential of the tumor.
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PMID:Expression of fas ligand in metastatic prostatic carcinoma: suggestive of possible clonal expansion of subpopulation with metastatic potential. 1176 14

The aim of this study was to evaluate the correlation between the detection of circulating melanoma cells and prognostic criteria for malignant melanoma such as clinical stage, tumor thickness and histological type of the primary tumor. Using a reverse transcriptase-polymerase chain reaction (RT-PCR) technique, melanoma cells were identified by detecting tyrosinase mRNA in peripheral blood from 58 patients with malignant melanoma classified according to the American Joint Committee on Cancer guidelines. The results of the RT-PCR assay for tyrosinase were related to two prognostic markers typically used to evaluate these tumors: clinical stage and thickness. Positive PCR results were more frequent in primary tumors measuring > 4 mm (83%) than in thinner tumors (1.1-4.0 mm, 74%; < or = 1.0 mm, 23%) (P = 0.005). No statistical correlation was found between the PCR results and histological appearance of the primary tumor. Although further studies are necessary, our results suggest the possible application of the PCR assay for tyrosinase mRNA in clinical evaluation of the prognosis of malignant melanoma.
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PMID:Reverse transcriptase-polymerase chain reaction detection of circulating tumor cells in patients with melanoma: correlation with clinical stage, tumor thickness and histological type. 1203 Oct 85

Minimal residual disease (MRD) evaluation in breast cancer patients is a promising tool to improve current staging procedures. In a previous work employing a CK-19-based reverse transcriptase-polymerase chain reaction (RT-PCR) technique for MRD detection, we identified a group of women who exhibited persistent negativity for this assay and for whom this technique was considered noninformative. In order to improve the yield of MRD detection in these patients, we evaluated the usefulness of RT-PCR detection of c-erbB-2 expression. We were able to detect up to 1 MCF-7 cell (positive for c-erbB-2 expression) in a mixture of 1,000,000 CCRF-CEM cells (negative for c-erbB-2 expression). We evaluated the specificity of this technique in the peripheral-blood mononuclear cells (PBMCs) of 20 healthy women and found that 2 of these women were positive for c-erbB-2 expression. In the PBMCs of a group of 16 women with breast cancer, 25% of the samples were positive for c-erbB-2 expression before chemotherapy. Except for race (P = 0.017), no other significant correlations were found, including c-erbB-2 expression in the primary tumor by immunoperoxidase. Interestingly, in the subgroup of 6 patients for whom this technique was informative, we found that 80% of the samples obtained while on chemotherapy were negative compared to only 10% obtained off treatment (P = 0.017). Additionally, 2 patients for whom CK-19 expression was noninformative had at least 1 c-erbB-2-positive sample. We conclude that this technique might be useful for MRD detection in breast cancer patients, but further studies are necessary to confirm our findings.
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PMID:Peripheral blood c-erbB-2 expression by reverse transcriptase-polymerase chain reaction in breast cancer patients receiving chemotherapy. 1219 78

A consistent, pathognomonic translocation, most commonly a balanced reciprocal translocation, t(X;18) (p11.2;q11.2), is found in more than 90% of synovial sarcomas. We report here a secondary chromosome change, der(22)t(17;22)(q12;q12), in addition to the primary t(X;18)(p11.2;q11.2) in a biphasic synovial sarcoma that occurred in the thigh of a 34-year-old woman. Although the karyotype of the primary tumor exhibited 46,X,t(X;18)(p11.2;q11.2), the recurrent tumor showed 46,X,der(X)t(X;18)(p11.2;q11.2),der(22) t(17;22)(q12;q12). The SYT-SSX1 fusion transcript was demonstrated in the primary and recurrent tumors using a reverse transcriptase polymerase chain reaction (RT-PCR). Southern blot analysis also confirmed that the detected messages were derived from the SYT-SSX fusion gene. However, we could not detect the EWS-E1AF fusion gene that has been reported to be generated through a t(17;22)(q12;q12) by RT-PCR. Furthermore, fluorescence in situ hybridization (FISH) with cosmid probes corresponding to loci flanking the EWSR1 region demonstrated no split of chromosome 22 in all analyzed interphase nuclei. To our knowledge, this is the first reported case of synovial sarcoma in which an additional (secondary) chromosome change, der(22)t(17;22)(q12;q12), has been demonstrated.
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PMID:Synovial sarcoma with a secondary chromosome change der(22)t(17;22)(q12;q12). 1237 9


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