PubMed Health⌕ Search

Biomedical subjects

M Negrini

Publications and source records attributed to M Negrini.

At least 37 records · Page 2Linked to original sources
PubMed2000

Acquired chromosome 11q deletion involving the ataxia teleangiectasia locus in B-cell non-Hodgkin's lymphoma: correlation with clinicobiologic features.

PURPOSE: To study the clinicobiologic significance of acquired 11q deletions involving the ataxia teleangiectasia locus (ATM+/-) in B-cell non-Hodgkin's lymphomas (NHL). PATIENTS AND METHODS: Fifty-three indolent lymphomas and 82 aggressive lymphomas were studied by conventional cytogenetic analysis and by fluorescence in situ hybridization using an 11q22-23 probe recognizing ATM sequences. Pertinent clinical data were collected. RESULTS: A hemizygous ATM deletion was seen in 44% to 88% of the interphase cells in 15 cases (11.1%); four patients had an indolent lymphoma (follicular center cell lymphoma), and 11 patients had an aggressive lymphoma (five mantle-cell lymphomas [MCLs] and six diffuse large-cell lymphomas). Dual-color hybridization studies showed ATM deletion to be possibly a secondary aberration in three patients with MCL. Ten out of 15 ATM+/- patients had a complex karyotype, 11 out of 15 had more than 90% abnormal metaphases (AA karyotype status), and +12, 13q14 deletion, and 17p13 deletion were seen in seven, four, and five cases, respectively. Patients with ATM+/- more frequently had a complex karyotype (P =.01) and the AA karyotype (P =.04) compared with patients without ATM+/-. With the exception of a poor performance status (P =.001), no correlation was found between ATM+/-, initial clinical variables, and complete remission rate; whereas a highly significant association was found with shorter survival (P <.0001). This cytogenetic lesion maintained its prognostic importance in multivariate analysis (P =.0004), along with performance status (P =.0006), serum lactate dehydrogenase level (P =.03), splenomegaly (P =.01), and histologic grade (P =.03). When analyzing indolent lymphomas and aggressive lymphomas separately, ATM+/- maintained its prognostic importance as an independent variable in both histologic groups (P =.0001 and P =.016, respectively). CONCLUSION: Though possibly not representing a primary genetic lesion in the majority of cases, the acquired ATM+/- status has clinicobiologic importance in NHL, possibly representing a major cytogenetic determinant of outcome.

Ataxia Telangiectasia↗
PubMed1999

Refinement of the LOH region 1 at 11q23.1 deleted in human breast carcinomas and sublocalization of 11 expressed sequence tags within the refined region.

Loss of constitutive heterozygosity at 11q23 has been detected in various human solid tumors. Here, we described the analysis of a series of normal and tumor pairs from 110 breast carcinomas for the presence of loss of heterozygosity at 11q23 loci. The overall frequency of LOH was 48%, confirming the importance of deletions at 11q23 in breast tumorigenesis. Previously, we have identified two independent regions of LOH at 11q23, the LOH region 1 at 11q23.1 and the LOH region 2 at 11q23.3. The most telomeric region was recently refined between loci D11S1345 and D11S1316, a region of about 1 Mb. However, the LOH region 1, most centromeric, was still not finely refined: the boundaries were defined by loci D11S2000 and D11S897, separated by about 8 Mb. Here, we refined its boundaries between loci D11S1347 and D11S927, a region of about 2 Mb. We have mapped 11 expressed sequence tags (ESTs) within this region and excluded another 20. This study represents a further step toward the identification of the putative tumor suppressor gene found within the LOH region 1 at 11q23.1.

Breast Neoplasms↗
PubMed1999

Molecular prenatal diagnosis of ataxia telangiectasia heterozygosity by direct mutational assays.

Ataxia telangiectasia (AT) is a severe autosomal recessive disease, rare but not infrequent in Italy. Owing to the seriousness of the disease, prenatal diagnosis has been attempted in the past by means of cytogenetic, biochemical, radio-biological and indirect molecular analyses. We performed the first direct molecular prenatal diagnosis of AT on a chorionic villi sample from a 37-year-old woman at the 10th week of pregnancy. She had two previous children suffering AT and two induced abortions. At molecular analysis her affected children were compound heterozygotes for mutations 7792C-->T in exon 55 (from the mother) and 8283delTC in exon 59 (from the father). The prenatal diagnosis was performed by two different operators in double-blind form. Mutation 7792C-->T was studied by restriction enzyme analysis using TaqI. Mutation 8283delTC was screened by heteroduplex analysis. The fetus was heterozygous for the mutation 7792C-->T (confirmed by sequencing). In order to verify the possible contamination by maternal DNA, polymorphic loci HLA-DRB1 and HLA-DQA1, together with microsatellite markers D6S259, D11S2000, D11S29, D11S1778 and D11S2179, were examined. All these loci were informative, showing that the fetus received only one allele from each parent. The heterozygosity for ATM mutation 7792C-->T was confirmed by molecular studies after the birth of a healthy male baby.

Adult↗
PubMed1999

Exon structure and promoter identification of STIM1 (alias GOK), a human gene causing growth arrest of the human tumor cell lines G401 and RD.

The stromal interaction molecular 1 gene (STIM1) encodes a type I trans-membrane protein of unknown function, which induces growth arrest and degeneration of the human tumor cell lines G401 and RD but not HBL100 and CaLu-6, suggesting a role in the pathogenesis of rhabdomyosarcomas and rhabdoid tumors. Here, we describe the STIM1 genomic organization including the identification of the promoter region. The gene consists of 12 exons that span a region larger than 250 kb between the genes RRM1 and NUP98. Nucleotide sequences of all exon-intron boundaries were determined and oligonucleotide primers for the amplification of individual exons were designed. The promoter region was identified within a 1.8-kb SacI fragment at the 5' end of the gene. In vitro CpG methylation of the promoter region indicated that transcription can be downregulated by this mechanism. The genetic tools developed in the present work will help to determine whether pathogenetic mechanisms that associate STIM1 with tumorigenesis involve mutations in coding sequences and/or promoter, and whether methylation could determine STIM1 transcriptional down-regulation in tumor samples.

Cell Division↗
PubMed1999

Transcriptional map of chromosome region 6q16-->q21.

We present the transcription map of chromosome region 6q16-->q21 by mapping fifteen known genes within this region. Five genes lay in the subregion containing a tumor suppressor gene, eight genes are located in the subregion harboring a senescence gene, and two genes are distal to the latter region. The precise location of the genes was obtained using a previously described translocation and deletion mouse/human hybrid panel. An even more accurate definition was possible for the genes spanning the senescence gene region, since a previously described YAC contig with its restriction map was available. From this transcription map it is possible to derive a large region of synteny with mouse chromosome 10.

Animals↗
PubMed1999

13q14 deletion in non-Hodgkin's lymphoma: correlation with clinicopathologic features.

BACKGROUND AND OBJECTIVE: 13q14 deletion frequently occurs as a single anomaly in chronic lymphocytic leukemia (CLL) with favorable prognosis. This study was performed to assess the distribution of 13q14 deletion in non-Hodgkin's lymphoma (NHL) and to analyze its correlation with salient clinicopathologic features. DESIGN AND METHODS: One hundred and twenty-five NHL were analyzed by cytogenetics and by interphase fluorescence in situ hybridization (FISH), using a 13q14 cosmid probe recognizing DNA sequences between the Rb gene and the D13S25 marker. Clinical records all patients were surveyed. RESULTS: A 13q14 rearrangement was present in the stemline in 10 patients; 15 additional cases were shown by FISH to carry 13q14 deletion in 55-90% of the interphase cells, giving a 20% overall incidence for this anomaly. Six of 44 patients had a low-grade NHL, 14/28 had mantle cell lymphoma (MCL), 5/42 had a high grade NHL (p<0.0001). There was not correlation between 13q, karyotype status and complexity. A statistically significant association was found between 13q-, presence of splenomegaly and PB involvement, lower probability of attaining complete remission (CR) and shorter survival. These findings were not simply a function of the association of 13q- with MCL. In multivariate analysis, a complex karyotype had prognostic importance (p=0.0078), along with age (p=0.01), histology (p=0.001), LDH (p=0.03), PS (p=0.001), sex (p=0.03) and splenomegaly (p=0.02). INTERPRETATION AND CONCLUSIONS: 13q14 deletion represented an early chromosome change and showed a preferential association with MCL, though it was found in virtually all principal histologic subtypes, irrespective of clinical stage, karyotype status and complexity. Patients with 13q14 deletions had a low CR rate, suggesting that genes relevant to lymphomagenesis are located in this chromosome segment that warrants molecular cytogenetic investigation.

Biomarkers, Tumor↗
PubMed1998

Molecular cloning and characterization of ZNF202: a new gene at 11q23.3 encoding testis-specific zinc finger proteins.

Two distinct regions of loss of heterozygosity (LOH) in breast carcinomas were previously identified at chromosome 11q23. With the aim of identifying a tumor suppressor gene, we undertook the isolation and characterization of genes within LOH region 2, defined between loci D11S1345 and D11S1316, which spans an area of about 1 Mb. Here, we describe the cloning and characterization of a new gene, ZNF202. The gene, which spans a genomic area of approximately 10 kb, is almost exclusively expressed in testis as a 4-kb mRNA. The predicted amino acid sequence of the protein product revealed significant homologies with zinc finger proteins, indicating that the ANF202 protein may function as a transcription factor. The presence of multiple CK2 and PKC phosphorylation sites suggests that its activity may be regulated by phosphorylation. The gene is also expressed in breast carcinoma cell lines. However, mutation analysis of 39 breast cancer samples revealed no evidence of mutations, indicating that ZNF202 is unlikely to be involved in the pathogenesis of this neoplasm. Nevertheless, a role for ZNF202 in the tumorigenic process of other tissues cannot be excluded.

Amino Acid Sequence↗
PubMed1998

The coding region of the Bloom syndrome BLM gene and of the CBL proto-oncogene is mutated in genetically unstable sporadic gastrointestinal tumors.

Microsatellite instability (MSI) characterizes the hereditary nonpolyposis colorectal cancer syndrome but is also found in sporadic tumors. Frameshifts in microsatellites found in the coding regions (CDRs) of the TGFbeta1-RII, IGFIIR, hMSH3, hMSH6, and BAX genes indicate that MSI is involved in tumorigenesis by targeting genes that are directly implicated in the tumorigenic process. To identify additional genes targeted for MSI, we performed an analysis of the GenBank database that revealed 21 microsatellite repeats located in the CDR of 18 genes (12% of the analyzed sequences) whose function could be potentially associated with the tumorigenic process. Mutational studies of 57 sporadic gastrointestinal tumor DNAs revealed the presence of length variations in three of them: (a) BLM; (b) CBL; and (c) HOXA1. In the BLM gene, we found a frameshift mutation in a polyadenine repeat, whereas in the CBL proto-oncogene, an expansion of a trinucleotide repeat was detected with no translation shift. These alterations were present in 18 and 9%, respectively, of the genetically unstable sporadic gastrointestinal tumors analyzed, but in none of the cancers without the mutator phenotype. These changes were present in the DNA from the tumor but not in that from normal cells of the same patient. The HOXA1 retraction of a trinucleotide repeat was as frequent in both types of cancers and was also found in some normal paired tissues, therefore behaving as a neutral polymorphism. Our data extend the spectrum of unstable microsatellites located in gene CDRs and suggest that BLM and possibly CBL are involved in gastrointestinal tumorigenesis. Based on its proposed function, the BLM gene could represent a link between MSI and chromosomal instability pathways, because MSI targeting of the BLM gene could generate hypermutability and/or chromosomal instability.

Adenosine Triphosphatases↗
PubMed1998

Transcriptional map of 170-kb region at chromosome 11p15.5: identification and mutational analysis of the BWR1A gene reveals the presence of mutations in tumor samples.

Chromosome region 11p15.5 harbors unidentified genes involved in neoplasms and in the genetic disease Beckwith-Wiedemann syndrome. The genetic analysis of a 170-kb region at 11p15.5 between loci D11S601 and D11S679 resulted in the identification of six transcriptional units. Three genes, hNAP2, CDKN1C, and KVLQT1, are well characterized, whereas three genes are novel. The three additional genes were designated BWR1A, BWR1B, and BWR1C. Full-length cDNAs for these three genes were cloned and nucleotide sequences were determined. While our work was in progress, BWR1C cDNA was described as IPL [Qian, N., Franck, D., O'Keefe, D., Dao, D. , Zhao, L., Yuan, L., Wang, Q., Keating, M., Walsh, C. & Tycko, B. (1997) Hum. Mol. Genet. 6, 2021-2029]. The cloning and mapping of these genes together with the fine mapping of the three known genes indicates that the transcriptional map of this region is likely to be complete. Because this region frequently is altered in neoplasms and in the genetic disease Beckwith-Wiedemann syndrome, we carried out a mutational analysis in tumor cell lines and Beckwith-Wiedemann syndrome samples that resulted in the identification of genetic alterations in the BWR1A gene: an insertion that introduced a stop codon in the breast cancer cell line BT549 and a point mutation in the rhabdomyosarcoma cell line TE125-T. These results indicate that BWR1A may play a role in tumorigenesis.

Beckwith-Wiedemann Syndrome↗
PubMed1998

Alternative splicing, genomic structure, and fine chromosome localization of REV3L.

We have localized a human homolog, REV3L, of the Saccharomyces cerevisiae REV3 gene on chromosome region 6q21. The full-length cDNA consists of 10,919 nucleotides, with a putative open reading frame of 9,159 bp for a predicted protein of 3,053 amino acids. The gene contains 33 exons in about 200 kb of genomic DNA. In contrast to the previously reported sequence, an additional exon and an alternative splicing site are demonstrated.

Alternative Splicing↗
PubMed1997

Molecular cloning and characterization of LOH11CR2A, a new gene within a refined minimal region of LOH at 11q23.

Deletions at chromosome 11q23 are frequent events in a variety of human neoplasms, including breast, lung, and ovarian carcinomas. Two common regions of loss of heterozygosity, shared between lung and breast carcinomas, have been previously identified at 11q23, suggesting that the same tumor susceptibility genes are altered in these two malignancies. One of these regions, refined in lung adenocarcinoma, is included between loci D11S1345 and D11S1328. Here, we describe the refinement of the same region in breast carcinomas and the characterization of a new gene found within this area. The gene, called LOH11CR2A, spans an area of approximately 40 kb and is transcribed at a low level in all the tissues in which it has been analyzed. The predicted amino acid primary sequence revealed no homology with other proteins that could help to elucidate a possible function for the LOH11CR2A protein. Here, we tested the hypothesis that LOH11CR2A could be a tumor suppressor gene. Analysis of human breast, lung, and ovarian carcinomas revealed the presence of several amino acid substitutions in the coding region of this gene. However, a role for these amino acid changes in the tumorigenic process could not established.

Amino Acid Sequence↗
PubMed1997

GOK: a gene at 11p15 involved in rhabdomyosarcoma and rhabdoid tumor development.

The expression of GOK, a gene recently identified at 11p15.5, was studied in breast cancer, rhabdomyosarcoma, and rhabdoid tumor cell lines. In these neoplasms, deletions at 11p15 and suppression of tumorigenicity induced by a normal human chromosome 11 were previously demonstrated. Whereas breast cancer cell lines express readily detectable levels of GOK mRNA, expression is absent in rhabdomyosarcoma and rhabdoid tumor cell lines. This is in contrast with the high expression of GOK in skeletal muscle, the normal tissue of origin of rhabdomyosarcomas, suggesting that down-regulation of GOK expression could be involved in tumor development. In agreement with this hypothesis, transfection of GOK cDNA into G401 derived from a rhabdoid tumor and RD cells derived from a rhabdomyosarcoma that do not express detectable levels of GOK mRNA, induced cell death. Because GOK expression is not compatible with growth of these tumor cells, these results support the hypothesis that loss of GOK expression plays a role in tumor establishment or progression and suggest that GOK may act as a recessive tumor suppressor gene in rhabdomyosarcomas and rhabdoid tumors. On the contrary, transfection of GOK cDNA into the breast cancer cell line HBL100 produced no detectable effects, indicating that the growth-suppressive effect of GOK in RD and G401 cells was specific. Because rhabdomyosarcomas have been observed in cases of Beckwith-Wiedemann syndrome, a genetic disorder linked to 11p15, a role of GOK in this disease cannot be excluded.

Chromosome Mapping↗
PubMed1997

Characterization of a 4-Mb region at chromosome 6q21 harboring a replicative senescence gene.

A 4-Mb region containing a senescence gene was defined at 6q21 by fluorescence in situ hybridization and deletion mapping after transfer of a normal human chromosome 6 to a BK virus-transformed mouse cell line. By screening three different yeast artificial chromosome (YAC) libraries, a YAC contig was constructed that covers the deleted region at 6q21. The contig is composed of 18 overlapping YACs with a size of 250-1800 kb and contains 3 CpG islands and 10 expressed sequence tags. By sequencing YACs and P1 artificial chromosomes, nine new sequence tagged sites and three new expressed sequence tags were detected that enrich the genetic resources of the region. The contig may also contain a fragile site, FRA6F, located close to a CpG island, which could be a landmark to localize the senescence gene. This YAC contig will be used to detect expressed sequences to clone and characterize the senescence gene at 6q21.

Animals↗
PubMed1997

Characterization of the human homologue of RAD54: a gene located on chromosome 1p32 at a region of high loss of heterozygosity in breast tumors.

A search of the Human Genome Sciences database of expressed sequence-tagged DNA fragments, for sequences containing homology to known yeast DNA recombination and repair genes, yielded a cDNA fragment with high homology to RAD54. Here we describe the complete cDNA sequence and the characterization of the genomic locus coding for the human homologue of the yeast RAD54 gene (hRAD54). The yeast RAD54 belongs to the RAD52 epistasis group and appears to be involved in both DNA recombination and repair. The hRAD54 gene maps to chromosome 1p32 in a region of frequent loss of heterozygosity in breast tumors and encodes a protein of M(r) 93,000 that displays 52% identity to the yeast RAD54 protein. The hRAD54 protein sequence additionally contains all seven of the consensus segments of a superfamily of proteins with presumed or proven DNA helicase activity. Mutations in genes with consensus helicase homology have been found in cancer-prone syndromes such as xeroderma pigmentosum and Bloom syndrome as well as Werner's syndrome, in which patients age prematurely, and the X-linked mental retardation with alpha-thalassemia syndrome, ATR-X. We have examined the hRAD54 gene in several breast tumors and breast tumor cell lines and, although the gene region appears to be deleted in several tumors, at present we have found no coding sequence mutations.

Amino Acid Sequence↗
PubMed1997

Cytogenetic and interphase cytogenetic characterization of atypical chronic lymphocytic leukemia carrying BCL1 translocation.

Conventional chromosome analysis (CCA) and fluorescent in situ hybridization (FISH) studies, using a 390-kb yeast artificial chromosome probe spanning the area of multiple breakpoints of the BCL1 locus at 11q13, were performed on 57 patients fulfilling the French-American-British criteria for the diagnosis of atypical B-cell chronic lymphocytic leukemia (CLL). To better define the incidence of 13q deletions and trisomy 12, FISH analysis was also performed using a cosmid probe that recognized a DNA sequence between the Rb gene and the D13S25 locus at band 13q14 and a chromosome 12-specific pericentromeric probe. All patients were characterized by cytoimmunological and hematological studies. Fourteen cases displayed three fluorescent signals in 41-98% interphase cells when hybridized to the BCL1 yeast artificial chromosome probe, documenting the presence of BCL1 translocation (BCL1-positive cases). The presence of t(11;14)(q13;q32) was ascertained in 12 cases using CCA and by dual color interphase FISH using the BCLI probe and a 14q telomere probe in 2 karyotypically normal cases. The remaining 43 cases had two signals in more than 95% interphase cells (BCL1-negative) and did not have the t(11;14) at CCA. Although 13q14 deletions were seen by means of CCA in only 5 of 14 BCL1-positive cases, hemizygous or homozygous deletions at band 13q14 were detected by FISH in 11 of 14 BCL1-positive cases, as compared with 17 of 43 BCL1-negative cases (P = 0.01). A subclone with trisomy 12 in addition to BCL1 translocation and del(13q14) was present in four BCL1-positive cases. We arrived at the following conclusions: (a) FISH with this BCL1 YAC probe is an efficient method for the detection of the t(11;14) and of the corresponding involvement of the BCL1 locus in this lymphoproliferative disorder; (b) the majority of BCL1-positive atypical CLLs by French-American-British criteria may carry 13q14 deletions; (c) the recognition of this cytogenetic subset of atypical CLL, sharing some immunological and cytogenetic features with mantle cell lymphoma, may be important, because these patients usually present isolated peripheral blood and marrow lymphocytosis, with or without mild to moderate spleen involvement, and may require early cytotoxic treatment.

Chromosomes, Artificial, Yeast↗
PubMed1997

Structure and expression of the human FHIT gene in normal and tumor cells.

The FHIT gene, encoded by 10 exons in a 1.1-kb transcript, encompasses approximately 1 Mb of genomic DNA, which includes the hereditary RCC t(3;8) translocation break at 3p14.2, the FRA3B common fragile region, and homozygous deletions in various cancer-derived cell lines. Because some of these genetic landmarks (e.g., the t(3;8) break between untranslated FHIT exons 3 and 4, a major fragile region that includes a viral integration site between exons 4 and 5, and cancer cell homozygous deletions in intron 5) do not necessarily affect coding exons and yet apparently affect expression of the gene product, we examined the FHIT locus and its expression in detail in more than 10 tumor-derived cell lines to clarify mechanisms underlying aberrant expression. We observed some cell lines with apparently continuous large homozygous deletions, which included one or more coding exons; cell lines with discontinuous deletions, some of which included or excluded coding exons; and cell lines that exhibited heterozygous and/or homozygous deletions, by Southern blot analysis for the presence of specific exons. Most of the cell lines that exhibited genomic alterations showed alteration of FHIT transcripts and absence or diminution of Fhit protein.

Acid Anhydride Hydrolases↗