ISSN:1052-9551    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Recent molecular analyses have contributed to our knowledge about the chromogranin/secretogranin (Cg/Sg) family and their utility in diagnostic pathology. The genes for five of these proteins have been cloned, and the deduced amino acid sequences have provided insights into the structure and possible functions of the Cgs/Sgs, including their role as prohormones. Northern hybridization and in situ hybridization histochemistry have provided a great deal of information about the tissue distribution of the Cg/Sg gene products. Some neoplasms such as small cell lung carcinomas, which have little stored Cg/Sg protein, have abundant cytoplasmic mRNAs that can be readily detected by hybridization studies. Some other neoplasms such as neuroblastomas have decreased CgA and increased Sgll mRNAs during maturation to ganglioneuromas. There is also a differential expression of Cgs/Sgs in some endocrine neoplasms such as parathyroid adenomas, which express abundant CgA mRNA and little CgB mRNA, and in pituitary prolactinomas, which express CgB mRNA but not CgA mRNA. The mRNA for CgA has been found unexpectedly in some neoplasms such as 15% of colonic adenocarcinomas. Thus, molecular approaches in the analysis of Cgs/Sgs should contribute to the diagnosis of endocrine neoplasms and may provide support for a molecular classification of neoplasms in diagnostic pathology.

ISSN:1052-9551    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Expression of the members of the chromogranin family [i.e., chromogranin A (CgA), chromogranin B, and secretogranin II (SgII)], the acidic proteins of the matrix of the chromaffin granules presently regarded as specific neuroendocrine markers, was investigated at gene and protein levels in a series of 14 cases of primary untreated neuroblastomas. Oligonucleotides and cRNA probes were employed for hybridization analysis of specific mRNAs (both by Northern blots and nonradioactive in situ hybridization); proteins were localized by immunocytochemistry. Expression of different amounts of each type of chromogranin was determined in all tumors. Cases found immunocytochemically negative were all positive by Northern blot and in situ hybridization. A better prognosis was associated with a higher relative expression of SgII; on the contrary, a worse outcome was observed in cases with a higher expression of CgA. These findings are consistent with the hypothesis that SgII is preferentially expressed in neuroblastomas undergoing neuronal differentiation. In cases of neuroblastomas, determination of expression levels of the different chromogranins in the tissues (and in the serum) can provide parameters of high diagnostic and prognostic value.

ISSN:1052-9551    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Surgical specimens of 15 patients with early and 12 patients with advanced squamous cell carcinoma of the vulva and the penis were examined for the presence of human papillomavirus (HPV) type 6, 11, 16, and 18 DNA by Southern blotting (SB) and polymerase chain reaction (PCR) analysis. By SB, HPV type 16 DNA was detected in all early carcinomas and 2 of 12 cases of advanced squamous cell carcinoma (ISCC) of the vulva and penis. PCR revealed HPV DNA in four additional cases of vulvar and penile ISCC negative by SB. Three cases contained HPV16 and one HPV18. Two cases of vulvar and penile Buschke-Lowenstein (BL) tumor with malignancy and one case of vulvar verrucous carcinoma were also examined by both techniques. While BL tumors were associated with DNA of HPV 6 or 11, no HPV association was found for verrucous carcinoma. Our results confirm that the detection rate of HPV DNA in early vulvar and penile carcinomas is much higher than in invasive carcinomas. In addition, we have shown that in the lower genital tract, 50% of cases of ISCC are HPV16 correlated. The absence of HPV DNA (types 6, 11, 16, and 18) in the remaining 50% of cases of ISCC thus suggests that vulvar and penile ISCC may have more than one pathogenetic pathway.

ISSN:1052-9551    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The translocation t(14;18)(q32;q21) occurs in 70% of follicular lymphomas and places the BCL2 proto-oncogene, normally located at 18q21. under the control of the immunoglobulin heavy chain (IgH) gene at 14q32. Its detection by the polymerase chain reaction (PCR), made possible by the close clustering of most of the BCL2 breakpoints in the major breakpoint region (MBR) of the gene, has numerous clinical applications. Since the PCR covers shorter lengths of DNA than Southern blotting, PCR-based tests may be more susceptible to microheterogeneity in breakpoint location. There have been no published studies of the impact of breakpoint microheterogeneity on the detection rate of this translocation by PCR. We studied 30 follicular lymphomas with the t(14;18), in which a BCL2 MBR rearrangement had previously been demonstrated and mapped by conventional Southern blotting, by PCR with the commonly used IgH and BCL2 MBR primers. Twenty-five cases (83%) had a junction fragment demonstrable by PCR. All three cases in which the MBR rearrangement mapped outside of the 4.3-kbHindIIIfragment containing the MBR, as determined by Southern blotting, were negative by PCR. In addition, two cases with rearrangements within theHindIIIfragment were also negative. All negative results were repeated at least once and were confirmed to be true negatives by actin PCR. Our results suggest that negative PCR results in this setting are attributable to small variations in BCL2 MBR breakpoint location and cannot be interpreted without the corresponding conventional Southern blotting data. With this caveat in mind, PCR analysis for the t(14;18) remains an extremely useful technique, especially in the follow-up and monitoring for minimal residual disease in previously characterized cases of follicular lymphoma.

ISSN:1052-9551    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The frequent cytogenetic abnormality—isochromosome 17q [i(17)q]—observed in medulloblastomas (MB) may result in altered expression of the oncosuppressor gene p53 that is located on 17p. p53 expression was therefore evaluated in five MBs and in one MB cell line derived from one of these tumors. Expression levels of p53 utilizing serially diluted unfractionated RNA from tumors and the cell line were assessed both by dot-blot and by reverse transcription (RT) followed by the polymerase chain reaction (PCR). The quality of RNA, efficiency of reaction, and transcript quantitation were determined by simultaneous transcription and amplification of a similarly sized fragment of the α-tubulin gene. All MBs showed low levels of expression of p53 compared to those found in normal tissues. p53 messenger RNA (mRNA) was significantly increased (two- to threefold) in the MB cell line compared to its tumor of origin and to the other MBs. Immunoperoxidase studies performed with monoclonal antibodies to the p53 protein product showed focal nuclear expression in one of five of the original tumors while most cells grown in vitro and in the xenograft were positive. The results indicate that (a) p53 mRNA was present in all MBs tested, thereby excluding the possibility of homozygous deletions of 17p, even though one tumor had i(17)q and another had a rearranged 17p; (b) p53 mRNA was not present in MBs in quantities significant enough to suspect inactivation by a combination of loss of heterozygosity and allelic point mutation; (c) p53 mRNA was overexpressed only in the MB cell line and xenograft suggesting an acquired p53 mutation conferring a growth advantage to selected clones of MB cells; and (d) RT-PCR is a rapid and simple nonisotopic technique that utilizes minimal quantities of total RNA for the assessment of gene expression.

ISSN:1052-9551    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

We describe a technique of in-situ hybridization using oligonucleotide probes employing the expression of immunoglobulin VH genes as a model. Optimal conditions for hybridization with the35S-labeled oligonucleotide probes were established with monoclonal B-cell lines that express VH genes of known nucleic acid sequence. The range of sensitivity and specificity achieved with this technique is documented. Under conditions of high stringency. this method can detect the expression of highly related VH hypervariable regions.

ISSN:1052-9551    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The polymerase chain reaction (PCR) uses in vitro enzymatic synthesis to amplify specific DNA sequences. PCR amplification can produce approximately 100 billion copies of one molecule of DNA in a few hours. PCR has revolutionized research in the biological sciences and medicine, and has influenced criminology and law. Several major scientific discoveries, including purification of DNA polymerase and elucidation of the mechanism of DNA replication, were essential for development of the present PCR technology. An overview of these discoveries and early work on in vitro DNA synthesis are presented. Basic PCR methodology, instrumentation, advanced PCR techniques, and applications are also discussed in this review. Several new amplification systems are mentioned. PCR is an extremely important and simple technology for research and diagnostic analyses of DNA and RNA. PCR technology and other amplification procedures will continue to produce novel applications in basic research and clinical medicine.

ISSN:1052-9551    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The new discipline of molecular pathology requires that high-quality, intact genomic DNA, mRNA, and proteins be available from frozen tissue samples. It is now necessary for pathology laboratories to establish consistent guidelines for the preparation and storage of frozen tissue samples in order to have properly preserved tissues available for diagnostic molecular techniques. Maintaining a frozen tissue bank requires a pathologist to oversee this program and to integrate it into the routine surgical pathology activities. A member of the laboratory technical staff can serve as a tissue bank coordinator and have responsibility for preparation of tissue samples, their systematic storage and retrieval, and routine maintenance of equipment and supplies. Tissue sampling must be done as soon as possible after excision of the specimen and is the responsibility of a qualified pathologist. The samples may be snap frozen without cryoprotection at - 78°C or colder for subsequent use in procedures requiring the extraction of genomic DNA, mRNA, or protein. To preserve tissue architecture and cytologic features for immunohisto-chemistry and in situ hybridization, the tissue should be frozen at - 78°C or colder with a cryoprotectant such as OCT. Long-term storage of the frozen tissue is recommended at - 140°C or colder in a locked liquid nitrogen freezer, and the record of sample inventory can easily be kept in a computerized database. Tissues sampled and stored under these conditions have been used successfully in a wide variety of molecular techniques. In addition to malignant tumor tissue, samples from benign lesions and normal tissues should be frozen. The establishment of a frozen tissue bank raises the issue of responsibility of the pathology laboratory to maintain the integrity of the frozen tissues for use in new diagnostic techniques. A frozen tissue bank operation is easily implemented in surgical pathology laboratories and can prove to be a valuable diagnostic and research asset.

ISSN:1052-9551    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1052-9551    

出版商:OVID    

年代:1992

数据来源: OVID