摘要:

Synovial sarcoma is characterized by a specific recurrent translocation t(X;18), resulting in either theSYT-SSX1orSYT-SSX2gene fusion. Because this is the primary genetic alteration in these tumors, we sought to identify the impact of molecular heterogeneity of the t(X;18) on cell proliferation, apoptosis, and epithelial differentiation in synovial sarcoma. Seventy-three patients with synovial sarcoma (18 biphasic, 55 monophasic) were selected on the basis of availability of tumor material for molecular and immunohistochemical analysis. Tumors were classified as biphasic on the basis of morphologic glandular differentiation.SYT-SSXfusion transcripts were examined by reverse transcriptase polymerase chain reaction using tumor RNA extracted from frozen or paraffin-embedded tissue. Cell proliferation was assessed immunohistochemically by the Ki-67 labeling index. Apoptosis was analyzed immunohistochemically with BAX and BCL2 antibodies and by the TUNEL method. Immunohistochemical evidence of epithelial differentiation was assessed using antibodies to cytokeratins and epithelial membrane antigen. Approximately two thirds of the tumors had anSYT-SSX1and one third had anSYT-SSX2fusion transcript. There was a strong association betweenSYT-SSXfusion type and histologic subtype. All biphasic synovial sarcomas had theSYT-SSX1fusion, whereas all tumors withSYT-SSX2were of monophasic morphology. There was, however, no association betweenSYT-SSXfusion type and expression of cytokeratins and epithelial membrane antigen among monophasic tumors. Tumors withSYT-SSX2had a significantly higher mean and median Ki-67 labeling index than those withSYT-SSX1, but a comparison of Ki-67 according to fusion type, histologic type, and sample source suggested that the main determinants of proliferation rate were the latter two factors. Specifically, monophasic tumors and metastatic tumors showed significantly higher Ki-67 scores. Apoptosis (by TUNEL) was rarely observed, consistent with prominent expression of the anti-apoptotic protein BCL2 in almost all cases. TUNEL, BCL2, and BAX results did not correlate withSYT-SSXfusion type. These data confirm the strong association ofSYT-SSXfusion transcript type with morphologic but not immunophenotypic epithelial differentiation in synovial sarcoma.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Rhabdomyosarcoma may be divided into three subtypes—embryonal, alveolar, and undifferentiated sarcoma—which can be distinguished by molecular analysis. The authors applied reverse transcriptase–polymerase chain reaction analysis (RT-PCR) to analyze tumor samples from 14 children with rhabdomyosarcoma for the presence of the chimericPAX3-FKHRtranscript resulting from the translocation t(2;13)(q35,q14). Both fresh and paraffin-embedded tissues were used. In only nine specimens was the RNA intact for the analysis. The chimeric transcript was identified in seven samples: four alveolar type, one embryonal type, and two undifferentiated sarcoma. Histologic review was performed in the three samples with discordance between the molecular and histologic findings. A sample from a patient with a diagnosis of embryonal rhabdomyosarcoma on presentation and expression ofPAX3-FKHRfusion transcript yielded a small focus of alveolar rhabdomyosarcoma and was reclassified as alveolar rhabdomyosarcoma. One of the samples from a patient with undifferentiated sarcoma was redefined as alveolar subtype; the diagnosis of the second undifferentiated sarcoma remained unchanged, in accordance with the histologic diagnosis.These findings further support the recommendation that molecular analysis be included in the diagnostic workup of childhood small round cell tumors to reach a more accurate diagnosis for tailoring of specific treatment.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Carcinoma of the breast is thought to evolve through a sequential progression from normal to proliferative epithelium and eventually into carcinoma. Here lumpectomy specimens from five patients were studied, selected for the presence of ductal hyperplasia without atypia, atypical ductal hyperplasia, ductal carcinoma in situ, and invasive ductal carcinoma. Laser microdissection of tissue allowed precise sampling and direct correlation of phenotypic and genotypic changes. Analyses of the samples revealed an increasing mean number of chromosomal changes occurring with increasing histologic severity, and for the first time chromosomal abnormalities were demonstrated in ductal hyperplasia without atypia. Chromosomal changes found in each of the four histologic entities included gains on 10q, 12q, 16p, and 20q and loss on 13q. In ductal hyperplasia without atypia, gain on 20q as well as loss on 13q was detected with high frequency (four of five samples). Alterations identified in more than 50% of atypical ductal hyperplasia samples included gains on 3p, 8q, 15q, and 22q and loss on 16q. In ductal carcinoma in situ, gain of DNA on 1q and 17q and loss on 4q were additionally found, and in invasive ductal carcinoma, further gains on 6p, 10q, 11q13, and 17p were identified. The chromosomal alterations occurring in the different histopathologic lesions strongly suggest that these regions harbor tumor suppressor genes or oncogenes significant for the development of ductal carcinoma of the breast.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Improved prognostic and predictive markers in breast cancer management would help considerably in therapeutic decision making, particularly in patients with early-stage breast cancer. Tumor factors currently used for prognostication and management decisions are tumor size, histologic type and grade, axillary lymph node status, and estrogen receptor content. The discovery of various somatic genetic alterations in breast cancer has raised the possibility that these may provide additional and independent prognostic and predictive information. Alterations of thep53tumor suppressor gene in particular have received the most attention as potential prognostic and predictive factors. In multivariate analysis,p53gene mutation is consistently associated with a two-to threefold increased risk of relapse and death from breast cancer. One of the major reasons preventing the introduction ofp53mutation as a routine marker to assist in therapeutic decision making is the lack of a simple, reproducible, and inexpensive assay. In the present study the authors optimized a polymerase chain reaction–based mutation screening method, fluorescence–single strand conformation polymorphism (F-SSCP), that allowsp53status to be assessed accurately and reproducibly in routinely handled, formalin-fixed and paraffin-embedded tumor specimens. The frequency ofp53mutation observed using F-SSCP in a consecutive series of invasive ductal breast carcinomas was 17% (28/164). The authors propose that the prognostic and predictive values ofp53mutation in breast cancer should be further evaluated in prospective, randomized studies using this standardized technique.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The oncogene-inducible secreted T1-S glycoprotein is overexpressed in invasive breast carcinomas in mice. As yet, nothing is known about the expression of T1-S in spontaneously occurring human cancers. A report follows on the overexpression of T1-S mRNA in 67% of primary invasive lymph node–negative breast carcinomas (31 of 46 patients) as determined by quantitative reverse transcriptase polymerase chain reaction. Overexpression of T1-S mRNA was independent of the tumor size, the histologic tumor type, and the estrogen—and progesterone—receptor status but was associated with high to moderate differentiation of the tumors (G1, G2). T1-S mRNA levels were low to nondetectable in resting normal mammary tissue and benign fibrocystic disease of the breast. Immunohistochemistry confirmed a low to moderate T1 immunoreactivity in epithelial cells of resting mammary tissue and benign fibrocystic disease and highly variable levels of T1 immunoreactivity in breast carcinoma cells. Kaplan-Meier analysis of disease-free survival during a median observation period of 61 months revealed a trend toward a reduced relapse rate and an extended relapse-free survival period for T1-S mRNA–overexpressing breast carcinomas. It is concluded that overexpression of T1-S receptor in lymph node–negative breast cancer may be a potential indicator for tumors with a low metastatic potential.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The p53 protein plays an important role in the control of the cell cycle and DNA repair. Mutations in theTP53gene may be a prognostic factor for certain forms of human cancer, with specific mutation sites being associated with significantly worse prognosis, particularly for colorectal and breast cancer. Thus, standardization of accurate, rapid, and cost-effective techniques for the detection ofTP53mutations is a high priority. At present, the only widely available technology that reliably detects and defines all mutations is DNA sequencing. However, the routine sequencing of the entireTP53gene in all breast and colorectal cancer cases in hospital laboratories is prohibitively costly, complex, and time consuming. In order for the analytical power of DNA to be accessed by the routine laboratory, initial screening using immunohistochemistry, which is widely used as a test for detection of accumulated, mutated protein, followed by heteroduplex analysis of exons 4 to 9 to detect frameshift mutations in immunohistochemistry-negative cases, is proposed. To illustrate the effectiveness of this approach, 28 cases of head and neck squamous-cell carcinomas that were known to containTP53mutations were retrospectively analyzed. All missense mutations stained positive on immunohistochemistry using the monoclonal antibody DO7, and all insertions and deletions, even those involving a single nucleotide, were positive using an extremely simple heteroduplex analysis. Only rare nonsense mutations were not detected by this strategy. Nevertheless, application of these results to published data suggests that the prescreening would detect 80% of mutations but would result in a 75% reduction in the sequencing load of the laboratory.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Tumor suppressor protein p53 is a positive regulator ofMDM2gene expression and the mdm2 protein can bind to p53, preventing the transactivation of p53 responsive genes, thus mimickingTP53mutation. The authors looked for alterations that could affect, directly and indirectly, p53 function in 13 patients with extrahepatic cholangiocarcinoma. Molecular analysis by single strand conformation polymorphism and DNA sequencing revealed thatTP53gene mutations occurred in only 2 of 13 cholangiocarcinomas. High levels of mdm2 protein were found, by immunohistochemical staining, in 61% of the cholangiocarcinomas and in almost all specimens (70%) displaying stabilized p53 protein in the absence and in the presence ofTP53mutations. The finding of co-overexpressed mdm2 and p53 proteins in cholangiocarcinomas indicates that they can upregulate the expression of mdm2 protein to a level sufficient for binding and accumulating p53 in a presumably inactive complexed form. The presence ofTP53mutations or upregulation ofMDM2gene expression in 9 of the 13 cholangiocarcinomas strongly supports that the impairment of the p53 pathway is an important and specific step in cholangiocarcinoma pathogenesis. At variance with other authors, no alteration ofp16ink4/CDKN2gene was observed in all 13 cholangiocarcinomas.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Somatostatin receptors type 2 (sst2) have been frequently detected in neuroendocrine tumors and bind somatostatin analogues, such as octreotide, with high affinity. Receptor autoradiography, specific mRNA detection and, more recently, anti-sst2 polyclonal antibodies are currently employed to reveal sst2. The aim of the present study was to investigate by three different techniques the presence of sst2 in a series of 26 neuroendocrine tumors of the lung in which fresh frozen tissue and paraffin sections were available. It was possible, therefore, to compare, in individual cases, RNA analysis studied by reverse transcriptase polymerase chain reaction (RT-PCR), in situ hybridization (ISH), and immunohistochemistry. A series of 20 nonneuroendocrine lung carcinoma samples served as controls. RT-PCR was positive for sst2 in 22 of 26 samples, including 15 of 15 typical carcinoids, 5 of 6 atypical carcinoids, and 2 of 5 small-cell carcinomas. The sst2 mRNA signal obtained by RT-PCR was strong in the majority (87%) of typical carcinoids and of variable intensity in atypical carcinoids and small-cell carcinomas. A weakly positive signal was observed in 5 of 20 control samples. In immunohistochemistry, two different antibodies (anti-sst2) were employed, including a monoclonal antibody, generated in the Department of Pathology, University of Turin. In the majority of samples a good correlation between sst2 mRNA (as detected by RT-PCR) and sst2 protein expression (as detected by immunohistochemistry) was observed. However, one atypical carcinoid and one small-cell carcinoma had focal immunostaining but no RT-PCR signal. ISH performed in selected samples paralleled the results obtained with the other techniques. A low sst2 expression was associated with high grade neuroendocrine tumors and with aggressive behavior. It is concluded that 1) neuroendocrine tumors of the lung express sst2, and there is a correlation between the mRNA amount and the degree of differentiation; 2) immunohistochemistry and ISH are reliable tools to demonstrate sst2 in these tumors; and 3) sst2 identification in tissue sections may provide information on the diagnostic or therapeutic usefulness of somatostatin analogues in individual patients with neuroendocrine tumors.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Extranodal malignant non-Hodgkin's lymphomas account for about 40% of lymphoid neoplasms, but few data are available concerning the genetic background of primary gastric diffuse large B-cell lymphoma (DLBCL). A study was performed of 27 primary gastric DLBCLs and 5 gastric DLBCLs with a concomitant low grade component of mucosa-associated lymphoid tissue-type lymphoma using comparative genomic hybridization (CGH), microsatellite studies, classic cytogenetics, and fluorescence in situ hybridization (FISH) to search for specific genetic aberrations. The most frequent aberrations were losses of material on chromosome 6q and gains of parts of chromosome 3. In three cases, a total of six high level DNA amplifications were detected, with five of them involving chromosomal regions not having been reported before in gastric DLBCL. A high overall concordance of 91.4% between microsatellite analysis and CGH was observed using DNA extracted from the same tissue block. The concordance achieved using DNA from different tissue blocks of the same patient was 85%. Microsatellite studies, CGH, FISH, and classic cytogenetics represent complementary techniques that facilitate a comprehensive view of genetic alterations in malignancies such as primary gastric DLBCL.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID