ISSN:1052-9551    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:1052-9551    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Large-cell anaplastic lymphomas (LCAL) are characterized by their distinctive morphology together with expression of the CD30 antigen. In addition, a chromosomal translocation, t(2;5) (p23; q35), can be detected in most cases. A significant proportion of LCALs carry rearrangements of the T-cell receptor-γ (TCR-γ) locus and display a T-cell phenotype. In about a third of the cases, another type of non-Hodgkin-lymphoma precedes LCAL. Early transformations of non-Hodgkin's lymphoma into LCAL might escape clinical detection in a significant number of cases. The existence of clonally related lymphoid cells within the lymph node infiltrates must be claimed in these cases. Recently, a small-cell-predominant variant of LCAL was described in which only few large tumor cells expressing the CD30 antigen are found together with numerous small lymphocytes, which are frequently CD30-. This observation in particular prompted us to investigate the clonal relationship of the tumor cell compartment and admixed small lymphocytes in one case of common LCAL with T-cell genotype. For this purpose, we chose to amplify rearranged TCR-γ sequences from single cells isolated from immunostained frozen sections by using a micromanipulator. A total of 119 cells were investigated. Amplification products were obtained in 17 of 79 CD3+cells, 12 of 30 CD30+cells, and three of 10 CD20+cells. The nucleotide sequences were determined in 28 cells by nonradioactive sequencing. In 11 CD30+cells, the predominant rearrangement of TCR-γ was identified. No clonal diversity was observed. The small CD3+lymphocytes were unrelated to the anaplastic CD30+tumor cells. This report describes a method to analyze rearrangements of the TCR-γ in single cells isolated from immunostained frozen sections. Application of this technique revealed an absence of clonal diversity in a case of LCAL and documented the polyclonal nature of admixed small CD3+lymphocytes.

ISSN:1052-9551    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

We determined, in a semiquantitative fashion, the level of expression of c-myc in 18 follicular center cell lymphomas and five non-neoplastic lymph nodes using reverse transcription and the polymerase chain reaction technique (RT-PCR). With this method, RNA is extracted from lymph node specimens and reverse-transcribed to produce cDNA, which is then amplified using primers specific for c-myc sequences that span introns, thus precluding amplification of genomic DNA. Amplified products are compared with β2-microglobulin sequences co-amplified in each case as a control for the quality of RNA extracted, RT, and PCR amplification. Using cell lines derived from Burkitt's lymphomas, the RT-PCR method yielded results equivalent to standard Northern blot analysis yet required smaller quantities of tissue. The c-myc transcripts were detected in all lymphoma cases studied (seven high, 11 low expression) and in all non-neoplastic lymph nodes. High or low c-myc expression was based on comparison with non-neoplastic lymph nodes. We conclude that the RT-PCR method is a sensitive, reliable method for measuring gene expression in lymphoma tissues and may be useful for studying the role of c-myc in follicular lymphomas.

ISSN:1052-9551    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

We have adapted and developed a PCR (polymerase chain reaction)-based technique for the T-cell receptor (TCR)-γ chain gene, which has subsequently been used for routine diagnosis. Variable-region oligonucleotide primers were chosen from subgroups I and II, and the joining region primer was from the J2segment. The primers were used to perform a32P-incorporation PCR, and the products were then separated on an 8% denaturing polyacrylamide gel. In our hands, this technique is more reliable than cold methods, when separation is performed on either agarose or nondenaturing polyacrylamide. The radioactive technique was used to look at 102 T-cell proliferations, of which eight of eight T-acute lymphoblastic leukemia (ALL), 24 of 34 T-non-Hodgkin's leukemia (NHL), and 35 of 60 large granular lymphocyte (LGL) expansions were clonal. Of 122 B-cell proliferations investigated, including 72 cases of B-cell lineage ALL, 36 demonstrated a T-cell rearrangement (33 ALLs and three myelomas). Samples from nonlymphoid tumors were tested and produced a normal distribution ladder of PCR products after autoradiography, a pattern also observed with antenatal and preoperative patients. The radiolabel-incorporation method detected an abnormal pattern of a ladder with prominent dark bands in 29 of 122 B-cell and 27 of 102 T-cell cases and in 0 of 49 of the nonlymphoid and normal samples. The abnormal banding patterns obtained in a proportion of the B- and T-cell cases was not readily discernible by nondenaturing-acrylamide or agarose-separation methods.

ISSN:1052-9551    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The mdm-2 protein is a 90-kD protein that forms a complex with the p53 protein, enabling cells from some human neoplasms to overcome the growth-suppressing activity of p53. Most non-Hodgkin's lymphomas lack p53 mutations, and the mechanism of inactivation of tumor suppressive function remains obscure. To assess the role of mdm-2 in lymphomagenesis, 22 cases were evaluated for mdm-2 gene amplification or rearrangement in Southern blots. Localization of the mdm-2 protein was performed on cryostat sections and compared with expression of the p53 gene product. No case exhibited mdm-2 gene amplification or rearrangement, but overexpression of nuclear mdm-2 gene protein product was found in three of six diffuse large cell (B-cell immunoblastic) lymphomas (30–70% of the tumor cells stained). The mdm-2 protein was absent from low- and intermediate-grade lymphomas with the exception of a few cells (5% or less) in four cases. The mdm-2-positive cases stained negative for p53. Southern blot analysis showed that samples overexpressing mdm-2 did not have amplification or rearrangement of the gene. In summary, amplification of the mdm-2 gene does not appear to play a prominent role in the pathogen-esis of non-Hodgkin's lymphomas, although overexpression of the protein gene product occurs, particularly in high-grade neoplasms.

ISSN:1052-9551    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Estrogen stimulates the proliferation of breast cancer cells and regulates the expression of other proteins, including the progesterone receptor (PR), via interaction with a unique estrogen receptor (ER), a ligand-inducible transcription factor that binds to regulatory DNA sequences associated with target genes. The best indirect evidence of an intact ER gene signaling system in a tumor is the demonstration of both ER and PR cytosol protein. The molecular basis of the ER (+)/PR (-) phenotype is unknown and may reflect either defective PR gene expression or alterations in the ER—specifically, inability of the ligand-receptor complex to effectively bind to regulatory sequences in DNA. To test the latter possibility, we evaluated 10 ER ( +)/PR (-) resected human breast cancers for small deletions and point mutations in the DNA binding domain of the ER gene. Exons 2 and 3 and their flanking intron sequences were selectively amplified using the polymerase chain reaction and then directly sequenced using the Sanger dideoxynucleotide method. A normal gene sequence was found in all cases studied. We conclude that sequence aberrations in the DNA binding domain of the ER are not a common cause of absent PR expression in ER (+)/PR (-) breast carcinomas.

ISSN:1052-9551    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Ras mutations have been found in thyroid lesions. Different studies have shown different frequencies of mutations among benign and malignant lesions. The presence of point mutations in codons 12 and 13 of the c-K-ras, c-H-ras, and N-ras genes was studied in 58 thyroid lesions (10 nodular goiters, 10 follicular adenomas, and 15 papillary, 10 follicular, and 13 anaplastic carcinomas). DNA was extracted from formalin-fixed paraffin-embedded tissue, and target sequences were amplified in vitro by the polymerase chain reaction. Mutations were detected by the presence of restriction-fragment-length polymorphisms either occurring naturally or introduced artificially by the use of mutant primers. No characterization of the mutations was performed. Results were correlated with clini-copathologic features and patient follow-up. One goiter showed a mutation at codon 13, c-K-ras. All follicular adenomas, including three hyalinizing trabecular adenomas, were negative. Four papillary carcinomas presented mutations (one at codon 13, c-K-ras; three at codon 12, N-ras). Two follicular carcinomas showed mutations at codon 12, N-ras. Five anaplastic carcinomas showed mutations (two at codon 12 and two at codon 13, c-K-ras; one at codon 12, N-ras). In summary, the results confirm that ras oncogenes play a role in thyroid tumorigenesis, probably at an early step. Ras mutations appear not to be related to prognosis.

ISSN:1052-9551    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Papillary renal cell carcinoma (papillary RCC) is an uncommon histologic variant of RCC with distinct gross, microscopic, and immunohistochemical features. Recent karyotypic analyses suggest that papillary RCC differs from other types of RCC at the genetic level as well. Whereas nonpapillary (clear cell, granular cell) RCC is characterized by deletions in chromosome 3p, papillary tumors reportedly exhibit a pattern of chromosomal trisomies, typically including chromosomes 7 and 17. To further examine the relationship between overrepresentation of these chromosomes and papillary histology, archival material from 36 papillary tumors was subjected to fluorescence in situ hybridization (FISH) analysis using α-satellite repeat probes specific to 7 and 17. Excess signals for chromosome 17 were detected in 22 of 28 (78%) low-grade papillary tumors (Fuhrman nuclear grades 1 and 2), and in seven of eight (87%) high-grade tumors (grades 3 and 4). Correlation of chromosome 17 FISH signals with karyotypes performed on two low-grade and three high-grade tumors was excellent. Among the cases without evidence of excess chromosome 17 were three unusual papillary tumors with sclerotic and hyalinized fibrovascular cores. In two cases, comparison was made of FISH signals from multiple, separate gross nodules of tumor; concordance for trisomic 17 signals was observed in one case, but not in the other. Chromosome 7 signals were overrepresented in all seven papillary tumors examined. DNA ploidy was determined in 19 of the 36 tumors; a relationship between DNA ploidy and polysomy 7 or 17 was not apparent. To examine the possible role of chromosome 3p deletions in the development of papillary RCC, 11 cases were studied for loss of heterozygosity (LOH) at one or more loci in the region of 3pl3–21. Only three of the 11 cases had LOH at these loci. The findings are discussed with respect to the development and progression of papillary RCC.

ISSN:1052-9551    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Fifty-two cases of malignant fibrous histiocytoma (MFH) were evaluated for amplification of the MDM2 gene, mutation of the P53 gene, accumulation of the P53 gene product, and their relation to disease-free and overall survival. All tests were carried out on formalin-fixed, paraffin-embedded tissue samples. Amplification of the MDM2 gene was detected in 15 of 52 cases (29%). Six of 52 cases (12%) demonstrated abnormalities of the P53 gene. Sequence analysis detected point mutations in four cases and a 1-base pair deletion in one case, whereas differential polymerase chain reaction (dPCR) indicated that the P53 gene had been entirely deleted in one case. Eight of 52 cases (15%) demonstrated staining for the P53 protein in >10% of tumor cells. The presence of MDM2 amplification did not have a significant effect on either disease-free or overall survival. Patients with accumulation of the P53 gene product did not differ in disease-free or overall survival from patients without P53 accumulation. Survival also was not significantly different in patients with genetic aberration in P53. However, when the patients were stratified by histologic grade, the results indicated that patients with alterations in the P53 gene may have shorter overall survival.

ISSN:1052-9551    

出版商:OVID    

年代:1996

数据来源: OVID