摘要:

t(11;18) is a recurrent chromosomal abnormality observed in mucosa-associated lymphoid tissue (MALT)-type lymphoma. API2 and MLT genes have been implicated. The authors devised a dual-color interphase fluorescence in situ hybridization (FISH) system to detect splitting of 11q22 and its fusion with 18q21. Subjects were 44 cases of extranodal lymphoma and cases of primary macroglobulinemia. Whenever RNA was available, reverse transcriptase–polymerase chain reaction followed by sequence analysis was performed. Positive cases by dual-color FISH analysis were restricted to MALT-type lymphoma and one case of primary macroglobulinemia. Among 24 cases of MALT-type lymphoma, 14 (58%) (4 gastric, 5 pulmonary, 3 orbital, 1 salivary, and 1 thyroid lymphomas) had splitting of the 11q22 region probes and fusion of signals suggesting the translocation of chromosome 11 and 18. Reverse transcriptase–polymerase chain reaction analysis showed the API2/MLT gene fusion in 9 of 10 cases. Sequence analyses showed three different modes of involvement of the MLT gene, whereas the breakpoint at API2 was the same. Monoclonal component of serum immunoglobulin M was observed in 3 of 14 positive cases for the translocation. Direct visualization using dual-color FISH on samples serves as a molecular tool for management of MALT-type lymphoma with API2/MLT gene fusion.

ISSN:1052-9551    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Increasingly, molecular biologic techniques have become important in the diagnosis of non-Hodgkin lymphomas. In the differential diagnosis of lymphoma(s) of small lymphocytes (LSL), reliable detection of t(11;14) or t(14;18) would confirm the diagnosis of mantle cell lymphoma (MCL) or follicle center lymphoma (FCL), respectively. A total of 87 LSL cases (27 MCL, 39 FCL, 17 small lymphocytic lymphoma [SLL], 3 marginal zone lymphomas, and 1 paraimmunoblastic variant of SLL) were diagnosed by a combination of light microscopy, immunohistochemistry, and flow cytometric immunophenotyping. Interphase fluorescence in situ hybridization (FISH) for t(11;14) and t(14;18) using dual-fusion probes (Vysis, Downers Grove, IL) was performed on touch (n = 69) or gravity (n = 18) preparations from these cases. Of 27 MCL cases tested, 25 (93%) had demonstrable t(11;14), none had t(14;18), and 2 were negative for t(11;14) and t(14;18). Twenty-five of 39 (64%) FCL cases had t(14;18), none had t(11;14), and the remaining FCL cases (14 cases [35%]) had neither t(11;14) nor t(14;18). All 17 (100%) SLL cases had neither t(11;14) nor t(14;18). All 3 (100%) marginal zone lymphoma cases had neither t(11;14) nor t(14;18). The case of paraimmunoblastic variant of SLL had t(11;14) and was negative for t(14;18). No discrepant [i.e., positive for both t(11;14) and t(14;18)] or false-positive cases were noted. Interphase FISH using these commercially available probes is a useful adjunct to light microscopy, immunohistochemistry, and flow cytometric immunophenotyping in the diagnosis of LSL. FISH can be performed successfully on archival single-cell preparations (touch preparations or gravity preparations) when fresh tissue is unavailable. No discordant or false-positive cases were identified.

ISSN:1052-9551    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Epstein-Barr virus (EBV) genome can be found in many malignant tumors in China. Previous data of interphase cytogenetics, by comparative genomic hybridization and/or fluorescence in situ hybridization, on nasopharyngeal carcinomas and natural killer cell-type non-Hodgkin lymphomas in Hong Kong have noted gains in chromosome 11. This study compares the frequency of chromosome 11 copy number gains in three different types of EBV-associated tumors in Hong Kong. Using alpha-satellite probes, the authors studied by fluorescence in situ hybridization 31 EBV-positive tumors comprising 10 EBV-positive gastric carcinomas, 8 lung lymphoepithelioma-like carcinomas, and 13 non-Hodgkin lymphomas. Trisomy or polysomy 11 was detected in 10 of 10 (100%) EBV-positive gastric carcinomas, 6 of 8 (75%) lung lymphoepithelioma-like carcinomas, and 4 of 13 (30.8%) non-Hodgkin lymphomas. Compared with the EBV-positive gastric carcinomas, the 10 EBV-negative gastric carcinomas that were also studied showed chromosome 11 copy number gains in 3 of 10 (30%), a significantly lower frequency. The authors conclude that gains in chromosome 11 are common in EBV-associated malignancies in Hong Kong, with the strongest association found in gastric carcinoma. There seems to be differences between EBV-associated tumors of different locations, and between gastric carcinomas with and without EBV.

ISSN:1052-9551    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Chondrosarcomas are malignant cartilaginous tumors. Most are located in the medullar cavity (central chondrosarcoma), and a minority develop in a preexisting osteochondroma (peripheral chondrosarcoma). The authors present karyotypes for 37 central, peripheral, juxtacortical, and dedifferentiated chondrosarcomas. Using loss of heterozygosity (LOH) analysis and DNA flow cytometry, the authors previously showed that central and peripheral chondrosarcomas probably evolve by different genetic mechanisms. Peripheral chondrosarcoma is characterized by genetic instability, as was previously shown by a high percentage of LOH and a broad range in DNA ploidy. The authors now show that all peripheral chondrosarcomas tested are aneuploid, combined with many nonspecific chromosomal aberrations. Two juxtacortical chondrosarcomas showed normal chromosome numbers combined with limited structural alterations, substantiating that juxtacortical and peripheral chondrosarcomas are two clinicopathologically different entities with a different genetic background. Central chondrosarcomas were previously found to be peridiploid with limited LOH, most frequent at 9p21. In the current study, chromosome 9 was involved in five of seven central chondrosarcomas compared with only one of four peripheral chondrosarcomas. Three central tumors showed involvement of the 9p12-22 region, suggesting an important role for chromosome 9 in the oncogenesis of central chondrosarcoma. Moreover, trisomy 22 was found in four central chondrosarcomas only.

ISSN:1052-9551    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

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.

ISSN:1052-9551    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant disease characterized by mild hypercalcemia, an inappropriately high parathyroid hormone level, and absence of hypercalciuria. Heterozygous inactivating mutations of calcium-sensing receptor (CaSR) are found in about two thirds of patients with FHH. Histologic examination of parathyroid glands in FHH is reported to show normal histology or chief cell hyperplasia. Thus, histologic features of the parathyroid glands in FHH vary, and there is no clear histologic criterion that indicates FHH. The authors have encountered three hypercalcemic patients with characteristic histologic features of enlarged parathyroid glands. Clusters of parenchymal cells were mixed with fat cells, and the area of fat cells was 33% to 49% of the total area. These features are similar to those described as parathyroid lipohyperplasia. Postoperative evaluation showed that fractional excretion of calcium was low in these patients. Direct sequencing of the polymerase chain reaction product showed that the first patient was heterozygous for an already reported inactivating mutation of CaSR (P55L). The second patient was also heterozygous for a novel inactivating mutation (R220W). The third was homozygous for an inactivating mutation (Q27R). These results indicate that histologic features of parathyroid lipohyperplasia suggest the presence of inactivating mutations of CaSR.

ISSN:1052-9551    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The ID genes are members of a family of genes that encode helix-loop-helix (HLH)-containing proteins. The Id proteins, unlike other HLH proteins, lack an adjacent DNA binding domain and hence act as dominant negative regulators of HLH transcription factors that have been implicated in control of cellular differentiation. Although the role of Id genes in murine development has been documented, their roles in human embryogenesis remain unknown. In this study, human male germ cell tumors (GCTs) were used as a model for examining the expression of the ID genes in various histologies that are reflective of different temporal phases of human development. In seminomas, little or no expression of ID1, ID2, and ID3 was detected, consistent with the uncommitted germ cell-like phenotype of this tumor histology. Likewise, GCTs with histologies reflective of extraembryonic and embryonic patterns of differentiation exhibited patterns of expression of the three ID genes often similar to those noted during murine development. It was also evident, as revealed by ID expression patterns, that despite the overall aberrant spatial differentiation patterns displayed by these tumors, some tissue–tissue interactions reminiscent of those observed during normal embryogenesis are retained. Thus, adult male GCTs offer a unique system in which the role of genes such as the IDs can be studied in human embryogenesis.

ISSN:1052-9551    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Epstein-Barr virus (EBV) is associated with several benign and malignant diseases, and blood tests for EBV viral load show promise as markers of disease burden in affected patients. A commercial quantitative PCR method (BioSource International) was recently introduced to facilitate measuring viral load. It relies on coamplification of EBV DNA and a spiked competitor in plasma or serum, followed by semiautomated product detection on enzyme-linked immunosorbent assay (ELISA) plates. In the current study, analytic performance characteristics were assessed, and the authors describe several methodologic improvements to facilitate laboratory implementation. Rapid DNA extraction was accomplished using commercial silica spin columns, heat-labile uracil-N-glycosylase was used to inhibit amplicon contamination, and inexpensive agarose gels were used to screen for polymerase chain reaction products requiring ELISA plate quantitation. Accuracy and precision were verified using EBV DNA standards derived from two cell lines and plasmid containing viral sequences. The assay was sensitive to as few as five template copies per polymerase chain reaction and was linear across four orders of magnitude (correlation coefficient 0.995). When applied to matched plasma and serum samples from 15 patients with nasopharyngeal carcinoma, both sample types yielded similar viral load results. This commercial EBV viral load assay provides sensitive and quantitative detection of EBV DNA using equipment already available in many molecular diagnostic laboratories.

ISSN:1052-9551    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

To obtain an adequate quality and quantity of DNA from formalin-fixed and paraffin-embedded tissue, six different DNA extraction methods were compared. Four methods used deparaffinization by xylene followed by proteinase K digestion and phenol-chloroform extraction. The temperature of the different steps was changed to obtain higher yields and improved quality of extracted DNA. The remaining two methods used microwave heating for deparaffinization. The best DNA extraction method consisted of deparaffinization by microwave irradiation, protein digestion with proteinase K at 48°C overnight, and no further purification steps. By this method, the highest DNA yield was obtained and the amplification of a 989-base pair &bgr;-globin gene fragment was achieved. Furthermore, DNA extracted by means of this procedure from five gastric carcinomas was successfully used for single strand conformation polymorphism and direct sequencing assays of the &bgr;-catenin gene. Because the microwave-based DNA extraction method presented here is simple, has a lower contamination risk, and results in a higher yield of DNA compared with the ordinary organic chemical reagent–based extraction method, it is considered applicable to various clinical and basic fields.

ISSN:1052-9551    

出版商:OVID    

年代:2001

数据来源: OVID