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Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Loss of a whole chromosome 5 or deletion of 5q are recurring abnormalities in malignant myeloid neoplasms. Chromosomal loss or deletion are the hallmarks of tumour suppressor genes, suggesting that a gene(s) located on 5q may function as a leukaemia suppressor gene. To determine the location of genes on 5q that may be involved in myeloid leukaemogenesis, we examined the breakpoints of the del(5q) in a series of 117 patients with malignant myeloid diseases. By comparing the breakpoints, we identified a small segment of 5q, consisting of band 5q31, that was deleted in each patient. This segment has been termed the critical region. A striking number of genes encoding haematopoietic growth factors have been mapped within or adjacent to the critical region. These include the genes encoding CSF-2, IL-3, IL-4, IL-5 and IL-9. By using fluorescence in situ hybridization, we have refined the localization of these genes to 5q31.1. To facilitate the identification of a tumour suppressor gene on 5q, we are currently preparing a physical map of 5q31. With FISH analysis of a series of cosmid and phage clones, we identified a number of clones within 5q31. By hybridizing these probes to metaphase cells with a del(5q) involving proximal or distal breakpoints within 5q31, we have narrowed the critical region to a small segment of 5q31 containing eight of the cosmids. In addition, we found that the five growth factor genes are excluded from this region. We have used dual colour FISH to determine the order of these cosmids, the order of the known genes mapped to 5q23-33 and the relationship of these genes to the critical region. To date, mutations of these genes in leukaemia cells have not been identified. The clinical features of myeloid diseases associated with a del(5q) are variable (RA 5q- syndrome v. AML); thus, once the involved gene is identified, it will be important to determine whether the same gene is involved in both types of myeloid disorders.
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PMID:Deletions of chromosome 5 in malignant myeloid disorders. 145 Nov 9

We have characterised a region of deletion on the long arm of chromosome 6 (6q) in six cases of acute lymphoblastic leukaemia, by fluorescence in situ hybridisation, using a series of YAC clones which map to 6q. Conventional cytogenetic analysis of four of these cases had been interpreted as showing terminal deletions of 6q. We demonstrated by FISH that in all cases the deletions were interstitial. D6S246 (6q16.3) was the only marker which was missing in all six cases, indicating a common region of deletion between the markers M6P1 at 6q14-15 and FYN at 6q21. Our results suggest the presence of a tumour suppressor gene within this interval.
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PMID:Deletion of a common region on the long arm of chromosome 6 in acute lymphoblastic leukaemia. 751 70

We report on an adenoid cystic-carcinoma (ACC) with a clonal deletion of 17p as the only karyotypic abnormality. Using different chromosome 17-derived probes we showed by FISH that the deletion encompassed the p53 tumour suppressor gene. Immunohistochemical analysis revealed overexpression of p53 protein in a subpopulation of cells, suggesting a mutation in the remaining p53 allele in these cells. Our findings provide novel information about possible progressional pathways in ACC, and demonstrate the value of combining conventional cytogenetic analysis with-molecular cytogenetic and immunohistochemical methods. This approach is particularly useful in cases with minor cytogenetic abnormalities at the border of visibility.
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PMID:Observations by chromosome banding, FISH and immunohistochemistry in an adenoid cystic carcinoma with del(17)(p13) as the sole deviation. 913 46

Research on the genetic basis of CLL is progressing at a rapid pace. The development of new techniques such as FISH, comparative genomic hybridisation (CGH) and a whole range of molecular methods is being applied to identify abnormalities in this relatively common B-cell leukaemia. The abnormalities may be of a different nature. There are some which are clearly associated with particular forms of the disease and usually with aggressive characteristics. The best examples are deletions at 11q23 seen in younger patients with generalised lymphadenopathy and inferior prognosis; trisomy 12, commonly associated with an increased proportion of prolymphocytes (CLL/PL) and more progressive disease; 17p abnormalities, chiefly mutations and deletions of p53, although rare, seem to be associated with transformation such as Richter syndrome, with CLL/PL and poor response to therapy. Abnormalities at 13q, though not correlated with particular clinical syndromes, are the subject of intense interest due to the possibility that one or more tumour suppressor genes relevant to the pathogenesis of CLL may be identified. Two areas in which work is being focused are 13q14 and 13q12. Finally, the incidence of familial cases of CLL, which has been known for a number of years, will lead to an international effort to collect familial cases, which ultimately will allow a genetic linkage study to discover a CLL "susceptibility gene". The presentations at the IWCLL were up-to-date, stimulating and pointed the way forward to further rapid progress in this exciting field.
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PMID:The search for genetic clues in chronic lymphocytic leukemia. 947 Oct 56

Cytogenetic and molecular analysis of soft tissue tumours has yielded a wealth of new information over the past 10-15 years. Many soft tissue neoplasms show specific karyotypic aberrations which have proved to be diagnostically valuable, and have also assisted in the understanding of pathogenetic mechanisms and rationalisation of classification systems (e.g. lipomatous tumours and Ewing's sarcoma/PNET). In certain clinical subsets, especially round cell sarcomas and fatty neoplasms, determination of karyotype (whether by conventional analysis, FISH or RT-PCR) has proved often to be useful in the diagnostic setting. Additionally the recognition of clonal abnormalities in both benign neoplasms as well as lesions formerly thought to be non-neoplastic (e.g. inflammatory "pseudotumour") has prompted reassessment of biologic concepts with regard to growth control. Inherited molecular genetic defects which predispose to soft tissue neoplasia (e.g. NF-1, Li-Fraumeni syndrome) have been characterised, leading to a greater understanding of tumour suppressor genes. Mesenchymal differentiation genes, the modes of action of which may help to expunge concepts of histogenesis, are being characterised. It is becoming clear that there exist growth control genes (such as the HMGI family) which, irrespective of differentiation, play an important role in a wide range of different mesenchymal tumours. Additionally it is evident that different histologic types of sarcoma (e.g. variants of liposarcoma) show quite different abnormalities of cell cycle control (notably at the G1-S checkpoint) and it seems increasingly likely that certain genetic aberrations, identifiable either at the chromosomal or individual gene level, may prove to be of prognostic relevance in sarcomas and may also open novel therapeutic avenues. While the validity of all molecular genetic data depends totally on skilled histological diagnosis and grading, there has never been a better time for close collaboration between pathologists and basic scientists in the study of soft tissue neoplasia.
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PMID:Soft tissue tumours: the impact of cytogenetics and molecular genetics. 947 86

Cytogenetic studies have demonstrated that oral squamous cell carcinomas (OSCCs) are usually characterised by complex karyotypes with many marker chromosomes. We analysed the genetic changes of six OSCC cell cultures by comparative genomic hybridisation (CGH). The CGH technique provides information on chromosomal gains and losses of the whole tumour genome in a single experiment and can therefore identify regions that harbour putative tumour suppressor genes (in the case of loss of chromosomal material) or oncogenes (in the case of gain or amplification of chromosomal material). Recurrent losses were detected at chromosome arms Xp and 3p (four cases). Gains consistently occurred at chromosome arms 8q and 9q (four cases) and at 1q, 3q, 5p, 7p, and 9p (three cases). The same six tumour cultures have previously been analysed by classical karyotyping. An important discrepancy between the two techniques was the number of losses detected: 55 with karyotyping versus 26 with CGH. On the basis of the cytogenetic complexity of these tumours and on FISH experiments that confirmed the CGH results, we conclude that genetic changes, particularly losses, can be more reliably detected by CGH analysis.
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PMID:Assessment of chromosomal gains and losses in oral squamous cell carcinoma by comparative genomic hybridisation. 950 25

Cellular, cytogenetic, and molecular evidence indicates that chromosome band 1p36 is often deleted in neuroblastoma cell lines and tumours, suggesting the presence of one or more tumour suppressor genes in this region. We used a multifaceted approach to analyse the commonly deleted region, 28 distal 1p-specific polymorphic loci were used to detect loss of heterozygosity (LOH) in a panel of primary neuroblastoma tumours. Thirty-two of 122 tumours (26%) demonstrated LOH at three or more loci. In addition, a patient with a constitutional deletion of 1p36.2-.3 and two neuroblastoma cell lines with 1p36 abnormalities were characterised by FISH. When combined with the LOH data, a single consensus region of deletion was defined proximally by PLOD and distally by D1S80, a region spanning approximately five megabases. Several proposed candidate tumour suppressor genes, including ID3, CDC2L1, DAN, PAX7, E2F2, TNFR2 and TCEB3, map outside of this region; however, the transcription factor HKR3 cannot be excluded. LOH for 1p is correlated with adverse clinical and biological features and a poor prognosis, but 1p LOH is not an independent predictor of overall survival. To identify additional candidate genes, an integrated physical map of 1p35-36 is being constructed. The current map includes 445 polymerase chain reaction (PCR)-formatted markers and 608 YACs. This map will help identify region-specific transcripts by direct selection and sequencing.
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PMID:Molecular analysis of the region of distal 1p commonly deleted in neuroblastoma. 951 32

We have characterised the DFFB gene, encoding the active subunit of the apoptotic nuclease DNA fragmentation factor (DFF40). DFFB maps to 1p36, near the imprinted putative tumour suppressor gene TP73. The DFFA gene (encoding the inhibitory DFF45 subunit) also maps to 1p36.2-36.3, and we show by FISH that DFFB lies distal to DFFA. We have also mapped a processed DFFB pseudogene to chromosome 9. DFFB itself has seven coding exons spanning 10 kb. Exhaustive mutation screening of 41 neuroblastomas and other tumours in which a 1p36 tumour suppressor gene is implicated showed no tumour-specific mutations. A coding region polymorphism was used to demonstrate uniformly biallelic expression in human fetal DFFB transcripts. Since the putative neuroblastoma tumour suppressor gene in distal 1p36 is predicted to be maternally expressed, the lack of imprinting and absence of somatic mutations in DFFB indicate that it is probably not the neuroblastoma tumour suppressor gene.
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PMID:Structure and mutation analysis of the gene encoding DNA fragmentation factor 40 (caspase-activated nuclease), a candidate neuroblastoma tumour suppressor gene. 1083 Sep 7

In childhood acute lymphoblastic leukaemia (ALL) a number of genetic changes have been identified which provide diagnostic and prognostic information with a direct impact on patient management. The most significant abnormalities include the translocation, t(12;21)(p13;q22), giving rise to the ETV6/AML1 gene fusion; BCR/ABL arising from t(9;22)(q34;q11); re-arrangements of the MLL gene; the E2A/PBX1 from the t(1;19)(q23;p13); re-arrangements of MYC with the immunoglobulin genes and re-arrangements of the T cell receptor genes. Chromosomal deletions, particularly those of the short arms of chromosomes 9 and 12 and the long arm of chromosome 6, have been postulated to be the sites of tumour suppressor genes (TSG). Numerical chromosomal abnormalities are of particular importance in relation to prognosis. High hyperdiploidy (50-65 chromosomes) is associated with a good risk, whereas the outlook for patients with near haploidy (23-29 chromosomes) is extremely poor. In view of the introduction of risk-adjusted therapy into the UK childhood ALL treatment trials, an interphase FISH screening programme has been developed to reveal chromosomal abnormalities with prognostic significance in childhood ALL.
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PMID:The genetics of childhood acute lymphoblastic leukaemia. 1103 43

In approximately 60% of sporadic meningiomas, the tumour suppressor gene NF2, located on chromosome 22q, is inactivated. Mutations in the NF2 gene have been specifically reported in transitional and fibrous, but not meningothelial, meningiomas. Since meningothelial meningiomas frequently occur in anterior parts of the skull base, the association between tumour localization, size, histological subtype and NF2 status was investigated in a group of 42 sporadic meningiomas. NF2 status was determined by LOH analysis, karyotyping and FISH. Tumour size and site were evaluated by CT scans and MRIs. A strong correlation between tumour localization in the anterior skull base and intact 22q was revealed (p=0.003). On the other hand, tumour localization at the convexity was associated with disruption of NF2 (p=0.023). Furthermore, an association between chromosome 22 status and histological subtype was observed: abnormalities of chromosome 22q were more frequent in transitional and fibrous meningiomas than in the meningothelial variant (p<0.001). Also, the meningothelial meningiomas were more often located in the anterior skull base (p<0.006). Based on these findings, it is concluded that an alternative histogenesis and genetic pathway is likely to exist for meningiomas arising in the anterior skull base.
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PMID:NF2 status of meningiomas is associated with tumour localization and histology. 1143 70


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