摘要:

Precise correlation of histomorphology with the results of molecular genetic analysis is difficult in gastric cancer tissue composed of intestinal and diffuse types. A novel microdissection procedure was applied to correlatep53andAPCallelic loss with histologic type and tumor stage (mucosal vs. invasive cancer) in formalin-fixed, paraffin-embedded specimens of 25 gastric cancers. In addition, mucosal and invasive lesions were dissected from each of 11 invasive gastric cancers to study progression, and allelic loss of thep53andAPCgenes was assessed. Thep53gene underwent loss of heterozygosity (LOH) in 4 of 4 informative cases of intestinal-type gastric cancer with mucosal lesions associated with invasion. By contrast, nop53LOH was found among 6 informative cases with mucosal cancer. LOH of the APC gene in both intestinal and diffuse types of cancer was detected in 4 of 7 and 5 of 6 informative cases, respectively. These data suggest that allelic deletion of thep53gene in intestinal-type gastric carcinoma predicts the invasive potential of mucosal cancer, and that in-activation of theAPCgene plays a role in the genetic tumorigenesis of both intestinal and diffuse types of gastric cancer. Microdissection can correlate genetic alterations with histologic morphology in gastric cancer.

ISSN:1052-9551    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

An approach is described for in situ polymerase chain reaction (ISPCR) based on cycling primed in situ synthesis (PRINS) conditions defined for α-satellite DNA. Using blood cell preparations subjected to limited fixation with paraformaldehyde. ISPCR cycling resulted in a gradual buildup of amplicon at the site of synthesis, as judged by the characteristic presence of paired nuclear spots corresponding to specific centromeres. Using longer cycling regimens, primers for single copy genes also generated paired nuclear spots in a primer-pair—specific manner. In this context, the amplification refractory mutation system (ARMS) was evaluated for in situ applications. In ARMS, allele-specific primers are used in such a manner that PCR proceeds only when an exact 3’ match between annealed primer and template is recognized by DNA polymerase. Using normal and mutant primers for the ΔF508 mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene as a model system, it was not possible to reliably differentiate between ARMS reactions by accumulation of direct labeled reaction product in cells, because of ARMS-independent non-specific labeling. However, by DNA extraction and reamplification with ARMS primers, it was shown that amplicon accumulates in cells in the expected primer/template-dependent manner crucial to mutation detection by ARMS. It was also shown that nonspecific signal is due to primer dimer formation, especially in the absence of true template DNA. The impact of primer dimer formation in generating a false-positive signal is discussed. The method described here enables a cell population to be analyzed for a given point mutation.

ISSN:1052-9551    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

A single synthesis cycle of the amplification refractory mutation system (ARMS) was applied to the analysis of K-rasalleles amplified by polymerase chain reaction and immobilized in streptavidin-coated microtiter plates. The ARMS cycle provided the specificity and molecular switch characteristics of a conventional ARMS assay. This allowed linear extension from an allele-specific primer and the incorporation of digoxigenin-labeled deoxyuridine monophosphate from digoxigenin-11-deoxyuridine triphosphate in the presence of the appropriate K-rasallele. Any digoxigenin-labeled deoxyuridine monophosphate substitution was then demonstrated by enzyme-linked immunoassay with a colorimetric endpoint. This method is capable of detecting underrepresented acquired mutations, and this has been shown by the unambiguous detection of specific K-rasmutations in cell line DNA/normal human genomic DNA admixtures. The characterization of K-rasmutations in frozen colorectal tumor samples and histologic material is also described.

ISSN:1052-9551    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Cyclin D1 (CD1) gene amplification is frequently observed in esophageal carcinosarcoma by differential polymerase chain reaction (DPCR). In this study, fluorescence in situ hybridization (FISH) was performed to show more direct evidence ofCD1gene amplification in patients with esophageal carcinosarcoma. FISH results were also compared with DPCR results studied previously. FISH analysis revealedCD1gene amplification in all four patients with esophageal carcinosarcoma.CD1gene amplification occurred with a high incidence in both components of esophageal carcinosarcoma, suggesting thatCD1gene amplification could have an important role in malignant transformation processes of esophageal carcinosarcoma. The results of the current study also suggest that FISH is a more sensitive method than DPCR. Because inactivation ofp16gene (which is a putative tumor suppressor gene) is thought to have similar oncogenic effects withCD1gene amplification. DPCR was used to examine whetherp16homozygous deletion occurs in esophageal carcinosarcoma. These results suggest that homozygous deletion of thep16gene occurs less frequently thanCD1gene amplification in esophageal carcinosarcoma. It does not seem to be an alternative event toCD1gene amplification, though the number of studied cases was small.

ISSN:1052-9551    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

An estimated 10% of adult cancer patients present with undifferentiated carcinoma. The diagnosis of germ cell tumor (GCT) in such patients can be difficult but has important implications for patient management. Male testicular GCT is characterized by an isochromosome 12p, i(12p), or additional 12p material, in some cases restricted to the 12p11.2-p12.1 region. A gain of 12p material can indicate that a tumor, which may not be present in the testis, is of germ cell origin. Formalin-fixed, paraffin-embedded samples are the most widely available material for diagnostic analysis and retrospective studies. We have compared the identification of 12p gain in snap-frozen samples with corresponding paraffin-embedded material from three clearly defined testicular GCTs using comparative genomic hybridization analysis. In this preliminary study, paraffin-embedded tumor samples of uncertain histogenesis from seven patients were then analyzed. Tumor samples from three of these patients showed a gain of 12p material, and in one patient, gain was restricted to the 12p11.2-p12 region. The clinical picture and response to therapy were generally consistent with the 12p status, though lack of 12p gain may not exclude a diagnosis of GCT.

ISSN:1052-9551    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The purpose of this study was to determine the frequency of infection by hepatitis A, B, C, D, E, and G in liver biopsy specimens from symptomatic patients and to correlate viral localization with the expression of interferon, interleukin 4, and tumor necrosis factor messenger RNA. Tissue biopsy specimens were taken from 78 patients as follows: 14 patients with transplants, 23 patients with cirrhotic livers, and 41 patients with chronic hepatitis. At least one of the hepatitis viruses was detected in 60 of 78 (77%) specimens; multiple infection was evident in 18 of 78 (23%) specimens. The overall incidence of the different viruses was as follows: 8% hepatitis A, 3% hepatitis B, 52% hepatitis C, 1% hepatitis D, 24% hepatitis E, 18% hepatitis G. Throughout each category, hepatitis C was the most common virus detected. No histologic variable correlated with either the percentage of infected hepatocytes per lobule or nodule or with the specific viral type. The cytokines localized to monocytes or lymphocytes adjacent to infected hepatocytes. These results demonstrate that viral infection is present in most biopsy specimens of patients with chronic hepatitis and liver transplants and that hepatitis C. E, and G account for most of the infections. The results also suggest that direct viral infection in conjunction with expression of different cytokines is important in the pathophysiology of viral-induced liver disease.

ISSN:1052-9551    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Alterations in microsatellite sequences have been reported in a variety of human cancers. Microsatellite instability is thought to reflect the inactivation of genes involved in DNA mismatch repair (MMR), which could predispose to the accumulation of further genetic errors in affected cells. Genomic instability in human cancers might also result from the inactivation of cell cycle controls such as the p53-dependent G1 checkpoint that prevents cell replication in response to DNA damage. High-risk human papillomavirus (HPV) is thought to contribute to the development of HPV-associated cancers, including cervical carcinoma, through the interaction of the E6 and E7 viral oncoproteins with two major cell cycle regulatory proteins, namely p53 and the retinoblastoma gene product (pRb). Although the high-risk HPV is prevalent in cervical carcinomas, viral DNA is not detected in a minor proportion of the cases. The HPV infection is insufficient for the development of cervical cancer, which indicates that additional genetic events are involved in the process. This study reports the potential role of MMR gene defects (in addition to or independent of HPV infection) in patients with cervical carcinogenesis. Microsatellite instability and HPV status were analyzed in a series of 54 patients with cervical carcinomas and in two associated cell lines. Microsatellite alterations were examined at 10 loci located in different chromosomes by using semiautomated fluorescent DNA technology and polymerase chain reaction. The HPV types were detected by a general primer polymerase chain reaction method. The results indicate that microsatellite instability is very infrequent in cervical carcinoma and occurs independently of HPV status.

ISSN:1052-9551    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Synovial sarcoma is characterized cytogenetically by an X;18 translocation [t (X:18) (p11;q11)] that results in the fusion of theSYTgene from chromosome 18 to either of two highly homologous genes at Xp11,SSX1orSSX2. Heterogeneity within the synovial sarcoma fusion junctions is rare. Examination of a primary monophasic synovial sarcoma for anSYT-SSXfusion transcript by reverse-transcription polymerase chain reaction revealed a smaller-than-expected product. Direct sequencing of the product disclosed a novelSYT-SSX1fusion transcript that contained an additional 51 bp of normalSSX1sequence but lost 135 bp of theSYTsequence. Detection of synovial sarcoma hybrid transcripts is useful for diagnosis and should include the recognition of distinct variants.

ISSN:1052-9551    

出版商:OVID    

年代:1998

数据来源: OVID