117 results on '"Varley, JM"'
Search Results
2. A novel TP53 splicing mutation in a Li-Fraumeni syndrome family: a patient with Wilms' tumour is not a mutation carrier
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Varley, JM, primary, McGown, G, additional, Thorncroft, M, additional, White, GRM, additional, Tricker, KJ, additional, Kelsey, AM, additional, Birch, JM, additional, and Evans, DGR, additional
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- 1998
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3. Chromosome instability is a predominant trait of fibroblasts from Li-Fraumeni families
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Boyle, JM, primary, Mitchell, ELD, additional, Greaves, MJ, additional, Roberts, SA, additional, Tricker, K, additional, Burt, E, additional, Varley, JM, additional, Birch, JM, additional, and Scott, D, additional
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- 1998
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4. Loss of heterozygosity at chromosome 9p in ductal carcinoma in situ and invasive carcinoma of the breast
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Marsh, KL, primary and Varley, JM, additional
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- 1998
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5. Frequent alterations of cell cycle regulators in early-stage breast lesions as detected by immunohistochemistry
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Marsh, KL, primary and Varley, JM, additional
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- 1998
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6. Absence of mutations in the ATM gene in breast cancer patients with severe responses to radiotherapy
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Appleby, JM, primary, Barber, JBP, additional, Levine, E, additional, Varley, JM, additional, Taylor, AMR, additional, Stankovic, T, additional, Heighway, J, additional, Warren, C, additional, and Scott, D, additional
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- 1997
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7. Li-Fraumeni syndrome – a molecular and clinical review
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Varley, JM, primary, Evans, DGR, additional, and Birch, JM, additional
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- 1997
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8. Identification of genetic changes associated with drug resistance by reverse in situ hybridization
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Hoare, SF, primary, Freeman, CA, additional, Coutts, JC, additional, Varley, JM, additional, James, L, additional, and Keith, WN, additional
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- 1997
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9. Mutation of the TP53 gene and allelic imbalance at chromosome 17p13 in ductal carcinoma in situ
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Munn, KE, primary, Walker, RA, additional, Menasce, L, additional, and Varley, JM, additional
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- 1996
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10. Allelic imbalance in the region of the BRCA1 gene in ductal carcinoma in situ of the breast
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Munn, KE, primary, Walker, RA, additional, Menasce, L, additional, and Varley, JM, additional
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- 1996
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11. Differential expression of translation-associated genes in benign and malignant human breast tumours
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Adams, SM, primary, Sharp, MGF, additional, Walker, RA, additional, Brammar, WJ, additional, and Varley, JM, additional
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- 1992
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12. A sequence previously identified as metastasis-related encodes an acidic ribosomal phosphoprotein, P2
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Sharp, MGF, primary, Adams, SM, additional, Elvin, P, additional, Walker, RA, additional, Brammar, WJ, additional, and Varley, JM, additional
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- 1990
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13. An evaluation of immunoreactivity for c-erbB-2 protein as a marker of poor short-term prognosis in breast cancer.
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Walker, RA, Gullick, WJ, Varley, JM, Walker, R A, Gullick, W J, and Varley, J M
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- 1989
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14. Germ line BAX alterations are infrequent in Li-Fraumeni syndrome.
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Barlow JW, Mous M, Wiley JC, Varley JM, Lozano G, Strong LC, and Malkin D
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- Alleles, Case-Control Studies, DNA Mutational Analysis, Female, Gene Frequency, Humans, Incidence, Li-Fraumeni Syndrome epidemiology, Male, Pedigree, Prognosis, Risk Assessment, Sampling Studies, Genetic Predisposition to Disease, Germ-Line Mutation genetics, Li-Fraumeni Syndrome genetics, Polymorphism, Genetic, Tumor Suppressor Protein p53 genetics
- Abstract
Multiple early-onset tumors, frequently associated with germ line TP53 mutations characterize the Li-Fraumeni familial cancer syndrome (LFS). LFS-like (LFS-L) families have lower rates of germ line TP53 alteration and do not meet the strict definition of LFS. This study examined 7 LFS cell lines and 30 LFS and 36 LFS-L primary leukocyte samples for mutations in the proapoptotic p53-regulated gene BAX. No germ line BAX mutations were found. A known BAX polymorphism was observed, yet there was no correlation between polymorphism frequency and TP53 status in either LFS or LFS-L. In summary, alterations of BAX are not responsible for cancers in TP53 wild-type LFS or LFS-L families.
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- 2004
15. Identification of recurrent regions of chromosome loss and gain in vestibular schwannomas using comparative genomic hybridisation.
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Warren C, James LA, Ramsden RT, Wallace A, Baser ME, Varley JM, and Evans DG
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- Adolescent, Adult, Aged, Child, Chromosome Aberrations, Chromosomes, Human, Pair 9 genetics, Female, Genes, Neurofibromatosis 2, Humans, Loss of Heterozygosity genetics, Male, Middle Aged, Neurofibromatosis 2 genetics, Recurrence, Chromosome Deletion, Gene Amplification genetics, Neuroma, Acoustic genetics, Nucleic Acid Hybridization methods
- Abstract
Background: Schwannomas are benign tumours of the nervous system that are usually sporadic but also occur in the inherited disorder neurofibromatosis type 2 (NF2). The NF2 gene is a tumour suppressor on chromosome 22. Loss of expression of the NF2 protein product, merlin, is universal in both sporadic and NF2 related schwannomas. The GTPase signalling molecules RhoA and Rac1 regulate merlin function, but to date only mutation in the NF2 gene has been identified as a causal event in schwannoma formation., Methods: Comparative genomic hybridisation (CGH) was used to screen 76 vestibular schwannomas from 76 patients (66 sporadic and 10 NF2 related) to identify other chromosome regions that may harbour genes involved in the tumorigenesis., Results: The most common change was loss on chromosome 22, which was more frequent in sporadic than in NF2 related tumours. Importantly, eight tumours (10%) showed gain of copy number on chromosome 9q34. Each of the two NF2 patients who had received stereotactic radiotherapy had non-chromosome 22 changes, whereas only one of eight non-irradiated NF2 patients had any chromosome changes. Three tumours had gain on 17q, which has also been reported in malignant peripheral nerve sheath tumours that are associated with neurofibromatosis type 1. Other sites that were identified in three or fewer tumours were regions on chromosomes 10, 11, 13, 16, 19, 20, X, and Y., Conclusions: These findings should be verified using techniques that can detect smaller genetic changes, such as microarray-CGH.
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- 2003
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16. Germline TP53 mutations and Li-Fraumeni syndrome.
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Varley JM
- Subjects
- Family Health, Genotype, Humans, Phenotype, Germ-Line Mutation, Li-Fraumeni Syndrome genetics, Tumor Suppressor Protein p53 genetics
- Abstract
There are now reports of nearly 250 independent germline TP53 (p53) mutations in over 100 publications. Such mutations are typically associated with Li-Fraumeni or Li-Fraumeni-like syndrome, although many have been identified in cohorts of patients with tumors considered to be typical of LFS. In general, the spectrum of mutations that has been detected in the germline reflects that found in tumors, although there are some notable exceptions in certain tumor types. Detailed knowledge of the pedigrees allows a comprehensive analysis of genotype-phenotype correlations and an understanding of the tumors that are associated with germline TP53 mutations. This review will discuss the spectrum of mutations and the methods for mutation detection, the tumors associated with inheritance of a germline mutation, and some of the ethical and clinical problems in patients with a germline TP53 mutation., (Copyright 2003 Wiley-Liss, Inc.)
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- 2003
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17. Low rate of TP53 germline mutations in breast cancer/sarcoma families not fulfilling classical criteria for Li-Fraumeni syndrome.
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Evans DG, Birch JM, Thorneycroft M, McGown G, Lalloo F, and Varley JM
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- Adult, Age of Onset, DNA Mutational Analysis, Female, Gene Frequency genetics, Genetic Testing statistics & numerical data, Humans, Li-Fraumeni Syndrome genetics, Breast Neoplasms genetics, Genes, p53 genetics, Germ-Line Mutation genetics, Li-Fraumeni Syndrome diagnosis, Sarcoma genetics
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- 2002
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18. Somatic glypican 3 (GPC3) mutations in Wilms' tumour.
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White GR, Kelsey AM, Varley JM, and Birch JM
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- DNA Primers chemistry, Glypicans, Humans, Male, Polymerase Chain Reaction, Polymorphism, Single-Stranded Conformational, Heparan Sulfate Proteoglycans genetics, Kidney Neoplasms genetics, Mutation genetics, Wilms Tumor genetics
- Abstract
Tumour and normal tissue from 41 male cases of Wilms' tumour were screened to determine the presence of sequence variants in the glypican 3 (GPC3) gene. Two non-conservative single base changes were present in tumour tissue only. These findings imply a possible role for GPC3 in Wilms' tumour development., (Copyright 2002 Cancer Research UK)
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- 2002
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19. Identification of a rare polymorphism in the human TP53 promoter.
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Attwooll CL, McGown G, Thorncroft M, Stewart FJ, Birch JM, and Varley JM
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- Base Pair Mismatch, DNA Mutational Analysis, Electrophoretic Mobility Shift Assay, Female, Gene Expression Regulation, Humans, Male, Pedigree, Reverse Transcriptase Polymerase Chain Reaction, Tumor Cells, Cultured, Genes, p53, Li-Fraumeni Syndrome genetics, Polymorphism, Genetic, Promoter Regions, Genetic genetics
- Abstract
The majority of families with classic Li-Fraumeni Syndrome (LFS) and a significant proportion of Li-Fraumeni-like (LFL) families have a germline mutation in the TP53 tumor suppressor gene. However around 20% of LFS and 60% of LFL families have no identifiable genetic defect in the coding region or splice junctions of TP53, and the genetic basis for cancer susceptibility in these families remains largely uncharacterized. To determine whether promoter mutations could be responsible for the Li-Fraumeni phenotype, we sequenced the TP53 promoter in index cases from members of classic LFS and LFL families without detectable TP53 mutations. We identified an identical single nucleotide deletion within the C/EBP- like site of the promoter in two out of eighteen such families (11%), compared to only one of a total of 366 control samples (0.3%). Although this result is highly significant (P=0.006, Fischer's exact test), the mutation did not affect the expression of TP53 in our hands. We provide evidence that this site is not utilized in the wild type TP53 promoter and further, that mutation of this site in LFS/LFL does not have a functional effect. We conclude that the sequence variant is a rare polymorphism arising within the TP53 promoter. However, the significantly increased frequency of this variant in LFS/LFL remains intriguing.
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- 2002
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20. RNA polymerase III transcription can be derepressed by oncogenes or mutations that compromise p53 function in tumours and Li-Fraumeni syndrome.
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Stein T, Crighton D, Boyle JM, Varley JM, and White RJ
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- Alleles, Amino Acid Substitution, Bone Neoplasms pathology, Fibroblasts metabolism, Gene Deletion, Germ-Line Mutation, Humans, Osteosarcoma pathology, Point Mutation, Proto-Oncogene Proteins c-mdm2, RNA, Transfer, Leu genetics, Tumor Cells, Cultured metabolism, Tumor Suppressor Protein p53 chemistry, Tumor Suppressor Protein p53 deficiency, Gene Expression Regulation, Neoplastic genetics, Genes, p53, Li-Fraumeni Syndrome genetics, Neoplasm Proteins metabolism, Nuclear Proteins, Oncogene Proteins, Viral physiology, Proto-Oncogene Proteins physiology, RNA Polymerase III metabolism, Repressor Proteins, Transcription, Genetic genetics, Tumor Suppressor Protein p53 physiology
- Abstract
RNA polymerase (pol) III synthesizes essential small RNAs, including tRNA and 5S rRNA. Wild-type p53 can repress pol III transcription both in vitro and in vivo. Many tumours carry substitutions in p53 which have selective effects on its functions. We identify tumour-derived mutations that compromise the ability of p53 to regulate pol III transcription. Furthermore, substitution R175H, the most common mutation in cancers, converts p53 from a repressor to an activator of pol III. Oncoproteins neutralize p53 in some tumours; we show that human papillomavirus E6 and cellular hdm2 can both release pol III from repression by p53. These data suggest that the restraining influence of p53 on pol III will be lost in many tumours. In addition to these features of sporadic cancers, some individuals inherit mutant forms of p53 and consequently suffer from Li-Fraumeni syndrome, showing genetic predisposition to certain malignancies. We find that pol III transcriptional activity is often highly elevated in primary fibroblasts from Li-Fraumeni patients, especially if the germline p53 mutation is followed by loss of the remaining allele. Our data suggest that p53 status can have a profound effect upon pol III transcription and hence on the biosynthetic capacity of cells.
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- 2002
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21. Delayed chromosome changes in gamma-irradiated normal and Li-Fraumeni fibroblasts.
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Boyle JM, Spreadborough AR, Greaves MJ, Birch JM, Varley JM, and Scott D
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- Aneuploidy, Animals, Cells, Cultured radiation effects, Chromosome Aberrations, Chromosomes, Human ultrastructure, Dose-Response Relationship, Radiation, Fibroblasts ultrastructure, Genes, p53, Genetic Predisposition to Disease, Genotype, Humans, Li-Fraumeni Syndrome pathology, Loss of Heterozygosity, Mice, Mice, Knockout, Radiation Tolerance genetics, Species Specificity, Time Factors, Chromosome Breakage, Chromosomes, Human radiation effects, Fibroblasts radiation effects, Gamma Rays adverse effects, Li-Fraumeni Syndrome genetics
- Abstract
Knockout mice with only one Trp53 allele (+/- genotype) are highly susceptible to radiation-induced cancers, possibly through numerical chromosome changes. Patients with the Li-Fraumeni syndrome, having heterozygous TP53 germline mutations (+/mut genotype), are also susceptible to spontaneous and radiogenic cancers. We have investigated the susceptibility of six Li-Fraumeni syndrome +/mut and six normal fibroblast strains to induced numerical and unstable structural aberrations at six population doublings after exposure to 3 or 6 Gy gamma rays. Four of the irradiated Li-Fraumeni syndrome strains showed small increases in both aberration types, similar to those seen in the normal strains. In two irradiated Li-Fraumeni syndrome strains, there were high levels of induced structural changes, and one of these showed a modest increase in hyperploidy. We suggest that enhanced sensitivity to delayed radiation-induced chromosome changes in Li-Fraumeni syndrome cells requires other genetic alterations in addition to TP53 heterozygosity, apparently in contrast to the situation in Trp53 heterozygous null mice. If such additional alterations occur in vivo in Li-Fraumeni syndrome patients, they may predispose them to radiogenic cancers, mainly through enhanced structural rather than numerical chromosome changes. Our findings raise questions about the validity of quantitative extrapolation of cytogenetic data from Trp53-defective mice to radiogenic cancer risk in humans.
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- 2002
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22. Destabilization of CHK2 by a missense mutation associated with Li-Fraumeni Syndrome.
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Lee SB, Kim SH, Bell DW, Wahrer DC, Schiripo TA, Jorczak MM, Sgroi DC, Garber JE, Li FP, Nichols KE, Varley JM, Godwin AK, Shannon KM, Harlow E, and Haber DA
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- Adult, Base Sequence, Checkpoint Kinase 2, Colonic Neoplasms genetics, DNA, Complementary genetics, Female, Gene Expression Regulation, Neoplastic, Gene Silencing, Genes, p53 genetics, Humans, Li-Fraumeni Syndrome enzymology, Loss of Heterozygosity, Male, Molecular Sequence Data, Pedigree, Protein Kinases metabolism, Tumor Cells, Cultured, Li-Fraumeni Syndrome genetics, Mutation, Missense, Protein Kinases genetics, Protein Serine-Threonine Kinases
- Abstract
Li Fraumeni Syndrome (LFS) is a multicancer phenotype, most commonly associated with germ-line mutations in TP53. In a kindred with LFS without an inherited TP53 mutation, we have previously reported a truncating mutation (1100delC) in CHK2, encoding a kinase that phosphorylates p53 on Ser(20). Here, we describe a CHK2 missense mutation (R145W) in another LFS family. This mutation destabilizes the encoded protein, reducing its half-life from >120 min to 30 min. This effect is abrogated by treatment of cells with a proteosome inhibitor, suggesting that CHK2(R145W) is targeted through this degradation pathway. Both 1100delC and R145W germ-line mutations in CHK2 are associated with loss of the wild-type allele in the corresponding tumor specimens, and neither tumor harbors a somatic TP53 mutation. Our observations support the functional significance of CHK2 mutations in rare cases of LFS and suggest that such mutations may substitute for inactivation of TP53.
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- 2001
23. Relative frequency and morphology of cancers in carriers of germline TP53 mutations.
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Birch JM, Alston RD, McNally RJ, Evans DG, Kelsey AM, Harris M, Eden OB, and Varley JM
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- Adolescent, Adult, Aged, Child, Child, Preschool, Cohort Studies, Family Health, Female, Genetic Predisposition to Disease, Heterozygote, Humans, Infant, Li-Fraumeni Syndrome pathology, Male, Middle Aged, Germ-Line Mutation, Li-Fraumeni Syndrome epidemiology, Li-Fraumeni Syndrome genetics, Tumor Suppressor Protein p53 genetics
- Abstract
The spectrum and frequency of cancers associated with germline TP53 mutations are uncertain. To address this issue a cohort of individuals from 28 families with Li-Fraumeni syndrome, segregating germline TP53 mutations was established. Predicted cancers were estimated by applying age, morphology, site and sex-specific UK cancer statistics to person-years at risk. Observed and predicted cancers were compared and two-sided P-values calculated. Cancer types occurring to excess and showing P-values <0.02, were designated strongly associated with germline TP53 mutations. These were removed from the data and a second round of analyses performed. Cancer types with P-values <0.02 and 0.02-0.05 in the second round analyses were considered moderately and weakly associated respectively. Strongly associated cancers were: breast carcinoma, soft tissue sarcomas, osteosarcoma, brain tumours, adrenocortical carcinoma, Wilms' tumour and phyllodes tumour. Carcinoma of pancreas was moderately associated. Leukaemia and neuroblastoma were weakly associated. Other common carcinomas including lung, colon, bladder, prostate, cervix and ovary did not occur to excess. Although breast carcinoma and sarcomas were numerically most frequent, the greatest increases relative to general population rates were in adrenocortical carcinoma and phyllodes tumour. We conclude that germline TP53 mutations do not simply increase general cancer risk. There are tissue-specific effects.
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- 2001
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24. Significance of intron 6 sequence variations in the TP53 gene in Li-Fraumeni syndrome.
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Varley JM, McGown G, Thorncroft M, Kelsey AM, and Birch JM
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- Genetic Predisposition to Disease, Humans, Polymorphism, Genetic, Genes, p53, Introns, Li-Fraumeni Syndrome genetics
- Abstract
Many polymorphisms have been reported in the TP53 gene. Some of these are within the coding region, and may affect the function of the p53 protein, others are within introns or non-coding regions, and their significance is unclear. Recently, a number of publications have claimed that polymorphisms within intron 6 are responsible for inherited predisposition to childhood malignancies, familial breast cancer, and Li-Fraumeni syndrome (LFS). We find no evidence for intron 6 sequence variants predisposing to LFS in our cohort of families and, furthermore, we show that some of the conclusions of other groups cannot be supported by data from our analysis.
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- 2001
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25. Correspondence re: A. Rothfuss et al., Induced micronucleus frequencies in peripheral blood lymphocytes as a screening test for carriers of a BRCA1 mutation in breast cancer families. Cancer Res., 60: 390-394, 2000.
- Author
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Baria K, Warren C, Roberts SA, West CM, Evans DG, Varley JM, and Scott D
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- Adult, Breast Neoplasms blood, Female, Genes, BRCA1, Genetic Testing methods, Germ-Line Mutation, Humans, Lymphocytes radiation effects, Male, Micronuclei, Chromosome-Defective radiation effects, Micronucleus Tests methods, Middle Aged, Radiation Tolerance genetics, Breast Neoplasms genetics, Lymphocytes ultrastructure, Micronuclei, Chromosome-Defective genetics
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- 2001
26. The relationship between radiation-induced G(1)arrest and chromosome aberrations in Li-Fraumeni fibroblasts with or without germline TP53 mutations.
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Boyle JM, Spreadborough A, Greaves MJ, Birch JM, Varley JM, and Scott D
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- Humans, Li-Fraumeni Syndrome pathology, Chromosome Aberrations, G1 Phase radiation effects, Genes, p53, Germ-Line Mutation, Li-Fraumeni Syndrome genetics
- Abstract
We previously showed that cultured fibroblasts from patients with the cancer-prone Li-Fraumeni (LF) syndrome, having heterozygous germline TP53 mutations, sustain less ionizing radiation-induced permanent G(1)arrest than normal fibroblasts. In contrast, fibroblast strains from LF patients without TP53 mutations showed normal G(1)arrest. We have now investigated the relationship between the extent of G(1)arrest and the level of structural chromosome damage (mainly dicentrics, rings and acentric fragments) in cells at their first mitosis after G(1)irradiation, in 9 LF strains with TP53 mutations, 6 without TP53 mutations and 7 normal strains. Average levels of damage in the mutant strains were 50% higher than in normals, whereas in non-mutant LF strains they were 100% higher. DNA double strand breaks (dsb) are known to act as a signal for p53-dependent G(1)arrest and to be the lesions from which chromosome aberrations arise. These results suggest that a minimal level of dsb is required before the signal for arrest is activated and that p53-defective cells have a higher signal threshold than p53-proficient cells. Dsb that do not cause G(1)blockage can progress to mitosis and appear as simple deletions or interact to form exchange aberrations. The elevated levels in the non-mutant strains may arise from defects in the extent or accuracy of dsb repair. In LF cells with or without TP53 mutations, the reduced capacity to eliminate or repair chromosomal damage of the type induced by ionising radiation, may contribute to cancer predisposition in this syndrome.
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- 2001
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27. Characterization of germline TP53 splicing mutations and their genetic and functional analysis.
- Author
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Varley JM, Attwooll C, White G, McGown G, Thorncroft M, Kelsey AM, Greaves M, Boyle J, and Birch JM
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- Alternative Splicing genetics, Cell Line, Fibroblasts physiology, Germ-Line Mutation genetics, Humans, Immunohistochemistry, Introns, Li-Fraumeni Syndrome genetics, Loss of Heterozygosity, Lymphocytes physiology, Neoplasms genetics, Reverse Transcriptase Polymerase Chain Reaction, Tumor Suppressor Protein p53 biosynthesis, Tumor Suppressor Protein p53 genetics, Tumor Suppressor Protein p53 physiology, Alternative Splicing physiology, Genes, p53 genetics, Germ-Line Mutation physiology
- Abstract
Germline TP53 splicing mutations have been described infrequently (>2%) in the literature, however in a series of 40 patients and families identified by our group in which there are germline TP53 mutations, seven affect splicing (18%). The low figure reported in the literature might reflect the method of mutation detection, which in many studies does not include all splice junctions. These data indicate that a significant proportion of TP53 germline mutations are currently unrecognized. We have carried out detailed studies of the effects of the different mutations on splicing, and see distinct variations in the effects of the same mutation in different patients. Furthermore we have identified the usage of a non-consensus splice donor site in four families with an intron 4 splice donor mutation.
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- 2001
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28. Immunohistochemical analysis of expression and allelotype of mismatch repair genes (hMLH1 and hMSH2) in bladder cancer.
- Author
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Kassem HS, Varley JM, Hamam SM, and Margison GP
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- Adaptor Proteins, Signal Transducing, Adult, Aged, Alleles, Allelic Imbalance, Carrier Proteins, DNA, Neoplasm genetics, Female, Gene Expression Regulation, Neoplastic, Humans, Immunohistochemistry, Loss of Heterozygosity, Male, Microsatellite Repeats genetics, Middle Aged, MutL Protein Homolog 1, MutS Homolog 2 Protein, Neoplasm Proteins analysis, Nuclear Proteins, Polymerase Chain Reaction, Proto-Oncogene Proteins analysis, Urinary Bladder Neoplasms metabolism, Urinary Bladder Neoplasms pathology, DNA-Binding Proteins, Neoplasm Proteins genetics, Proto-Oncogene Proteins genetics, Urinary Bladder Neoplasms genetics
- Abstract
Mutation of human homologues of DNA mismatch repair (MMR) genes in tumours has been shown to be associated with the phenomenon of microsatellite instability (MSI). Several studies have reported the occurrence of MSI in bladder cancer, but evidence of involvement of MMR genes in the pathogenesis of this cancer is still unclear. We therefore utilized quantitative immunohistochemical (IHC) image analysis and PCR-based allelotype analysis to determine hMLH1 and hMSH2 genes alteration in a cohort of Egyptian bladder cancer samples. IHC analysis of 24 TCC and 12 SCC revealed marked- intra and intertumour heterogeneity in the levels of expression of the two MMR proteins. One TCC lost MLH1 expression and one lost MSH2, (1/24, 4%), and one SCC lost MSH2 (1/12, 8%). A large proportion of analysed tumours revealed a percentage positivity of less than 50% for MLH1 and MSH2 expression (44% and 69%, respectively). Complete loss of heterozygosity in three dinucleotide repeats lying within, or in close proximity to, hMLH1 and hMSH2 was rare (2/57, (4%) for MLH1; and 1/55, (2%) for MSH2), however allelic imbalance was detected in 11/57 (hMLH1) and 10/55 (hMSH2) at any of the informative microsatellite loci. These alterations in structure and expression of DNA MMR genes suggest their possible involvement in the tumorigenesis and/or progression of bladder cancer.
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- 2001
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29. Genomic alterations associated with loss of heterozygosity for TP53 in Li-Fraumeni syndrome fibroblasts.
- Author
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Burt EC, James LA, Greaves MJ, Birch JM, Boyle JM, and Varley JM
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- Cells, Cultured, Chromosome Deletion, Fibroblasts diagnostic imaging, Fibroblasts physiology, Germ-Line Mutation genetics, Humans, Li-Fraumeni Syndrome pathology, Microsatellite Repeats genetics, Nucleic Acid Hybridization, Ultrasonography, Genes, p53 genetics, Li-Fraumeni Syndrome genetics, Loss of Heterozygosity genetics
- Abstract
Studies of Li-Fraumeni syndrome fibroblasts heterozygous for germline TP53 mutations have shown that loss of heterozygosity (LOH) occurs during passaging and is associated with genomic instability, such as chromosomal aberrations and aneuploidy to investigate the genomic changes associated with LOH in Li-Fraumeni (LF) fibroblasts, we have analysed cell strains at increasing population doublings (PD) using Comparative Genomic Hybridization (CGH). We have looked at three groups of cell strains: LF mutation-carrying strains which showed LOH for TP53, LF mutation-carrying strains which did not show LOH, and strains from normal individuals. Using CGH, we have detected loss of distinct chromosomal regions associated with LOH in 4 out of 5 mutation-carrying strains. In particular we have found loss of chromosomal regions containing genes involved in cell cycle control or senescence, including loss of 9p and 17p in these strains. Other recurrent changes included loss of chromosomes 4q and 6q, regions shown to contain one or more tumour suppressor genes. No genomic alterations were detected at cumulative PD in the normal strains or in the LF mutation-carrying strains which did not show LOH for TP53. We have also analysed the three groups of strains for microsatellite instability and somatic TP53 mutations, and have found genetic alterations in only one strain.
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- 2000
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30. Genomic structure and expression profile of LPHH1, a 7TM gene variably expressed in breast cancer cell lines.
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White GR, Varley JM, and Heighway J
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- Alternative Splicing, Animals, Base Sequence, Brain metabolism, Breast Neoplasms, Cattle, DNA Primers, Exons, Gene Expression, Gene Library, Humans, Introns, Molecular Sequence Data, Mutation, Open Reading Frames, Rats, Receptors, G-Protein-Coupled, Reverse Transcriptase Polymerase Chain Reaction methods, Tumor Cells, Cultured, Membrane Proteins genetics
- Abstract
Gene identification studies, centred on a region of overlapping loss of heterozygosity in breast tumours within band 1p31.1, lead to the characterisation of LPHH1, a novel human 7TM gene. The coding sequence of LPHH1 extends over a 60 kb region and comprises in excess of 28 exons. Alternative splicing occurs minimally at five positions, four of which are within the coding sequence. The fifth region of alternative splicing occurs at the extreme 5' end of the transcript. A clear tissue specific bias in alternative exon selection is observed to some degree at all five positions, including the extreme 5' region, which raises the possibility of multiple and perhaps tissue specific promoters. One such putative promoter region, which appears to be utilised predominantly in breast cancer cells, has been identified. LPHH1 is highly evolutionarily conserved, with the simplest (19 exon) gene product being 95% identical between human and rat. Comparison of the alternatively spliced exons between three species, where data are available, has so far revealed 100% identity in the encoded peptide sequences, suggesting conservation of a functional aspect of this splicing. Gene expression has been observed in all tissues and cell lines tested, with the exception of lymphoblastoid and multiple myeloma lines, where there appears to be only a very low level of transcription. LPHH1 also appears to be downregulated in human bone marrow. These data are consistent with a role for the gene products in adhesion-mediated signalling. Analysis of a panel of breast tumour cell lines revealed that a number apparently overexpressed the gene whilst others showed very low levels of transcription. In one case, the overexpression correlated with a low level increase in gene copy number in the tumour line. In addition to differences in the overall levels of expression, LPHH1 mRNAs were alternatively spliced to varying degrees with shifts in the major gene product to truncated or altered forms in some lines. No somatic LPHH1 mutations were detected through sequence analysis of four primary breast tumours that showed loss of the adjacent 1p31.1 marker D1S207.
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- 2000
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31. Assignment of TTC4 to human chromosome band 1p31.3 and a pseudogene TTC4P to 7p14-->p13 by in situ hybridization.
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Hey Y, Brintnell B, James LA, and Varley JM
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- Amino Acid Motifs, Base Sequence, Breast Neoplasms genetics, Chromosome Banding, Chromosomes, Artificial, Yeast genetics, Exons genetics, Humans, Introns genetics, Physical Chromosome Mapping, Polymerase Chain Reaction, Chromosomes, Human, Pair 1 genetics, Chromosomes, Human, Pair 7 genetics, In Situ Hybridization, Fluorescence, Pseudogenes genetics
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- 2000
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32. Heterozygous germ line hCHK2 mutations in Li-Fraumeni syndrome.
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Bell DW, Varley JM, Szydlo TE, Kang DH, Wahrer DC, Shannon KE, Lubratovich M, Verselis SJ, Isselbacher KJ, Fraumeni JF, Birch JM, Li FP, Garber JE, and Haber DA
- Subjects
- Alleles, Apoptosis, Brain Neoplasms genetics, Breast Neoplasms genetics, Checkpoint Kinase 1, Checkpoint Kinase 2, Female, G1 Phase, Genes, p53, Genetic Predisposition to Disease, Heterozygote, Humans, Li-Fraumeni Syndrome enzymology, Li-Fraumeni Syndrome pathology, Male, Pedigree, Polymorphism, Genetic, Protein Kinases genetics, Protein Serine-Threonine Kinases metabolism, Sarcoma genetics, Signal Transduction, Tumor Cells, Cultured, G2 Phase, Genes, Tumor Suppressor, Germ-Line Mutation, Li-Fraumeni Syndrome genetics, Protein Serine-Threonine Kinases genetics
- Abstract
The hCHK2 gene encodes the human homolog of the yeast Cds1 and Rad53 G2 checkpoint kinases, whose activation in response to DNA damage prevents cellular entry into mitosis. Here, it is shown that heterozygous germ line mutations in hCHK2 occur in Li-Fraumeni syndrome, a highly penetrant familial cancer phenotype usually associated with inherited mutations in the TP53 gene. These observations suggest that hCHK2 is a tumor suppressor gene conferring predisposition to sarcoma, breast cancer, and brain tumors, and they also provide a link between the central role of p53 inactivation in human cancer and the well-defined G2 checkpoint in yeast.
- Published
- 1999
- Full Text
- View/download PDF
33. Identification of a novel fusion gene involving hTAFII68 and CHN from a t(9;17)(q22;q11.2) translocation in an extraskeletal myxoid chondrosarcoma.
- Author
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Attwooll C, Tariq M, Harris M, Coyne JD, Telford N, and Varley JM
- Subjects
- Amino Acid Sequence, Base Sequence, Chromosomes, Human, Pair 17, Chromosomes, Human, Pair 9, Humans, Molecular Sequence Data, Receptors, Steroid, Receptors, Thyroid Hormone, Reverse Transcriptase Polymerase Chain Reaction, Translocation, Genetic, Artificial Gene Fusion, Chondrosarcoma genetics, DNA-Binding Proteins genetics, Nerve Tissue Proteins, Nuclear Proteins genetics, TATA-Binding Protein Associated Factors, Transcription Factors genetics
- Abstract
A proportion of extraskeletal myxoid chondrosarcomas (EMC) have been shown to have a characteristic translocation t(9;22)(q22;q12) involving the EWS gene at 22q12 and the CHN orphan nuclear receptor gene at 9q22. This translocation appears to be largely specific for EMC, but has not been detected in all such tumours. We report here a case of EMC with a t(9;17)(q22;q11.2) as the sole chromosome abnormality. We have determined that the translocation results in the fusion of the entire coding region of CHN to the N-terminal transactivation domain of RBP56/hTAFII68. This is the first report of a translocation involving RBP56/hTAFII 68, a protein with sequence homology to both EWS and TLS/FUS. The involvement of RBP56/hTAFII68 may explain some unusual features of the tumour.
- Published
- 1999
- Full Text
- View/download PDF
34. Human papillomavirus type 16 E6 variants in cervical carcinoma: relationship to host genetic factors and clinical parameters.
- Author
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Brady CS, Duggan-Keen MF, Davidson JA, Varley JM, and Stern PL
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Genes, MHC Class I, Genes, MHC Class II, Genes, p53, Humans, Middle Aged, Neoplasm Staging, Papillomaviridae classification, Papillomavirus Infections virology, Point Mutation, Polymerase Chain Reaction, Polymorphism, Genetic, Sequence Analysis, DNA, Tumor Virus Infections virology, Uterine Cervical Neoplasms pathology, Genetic Variation, Oncogene Proteins, Viral genetics, Papillomaviridae genetics, Repressor Proteins, Uterine Cervical Neoplasms virology
- Abstract
Infection with human papillomavirus type 16 (HPV-16) confers a high risk for the development of cervical neoplasia. Variants of this virus may interact differentially with host genetic factors, possibly altering the disease course. Thus, HPV-16 E6 variants may differ in their ability to degrade p53 whereas the polymorphic p53 alleles may provide more or less susceptible substrates for the viral oncogene product. Also, E6 variants may differ in immunogenicity by generating different peptides for presentation by polymorphic HLA molecules to specific T cells. This study examines HPV-16 E6 sequence variation in cervical carcinomas from the UK and its relationship to polymorphism of HLA and p53 and to clinical parameters. Sequence analysis of the HPV-16 E6 ORF from 77 tumour biopsies detected the viral prototype sequence in 38% of cases. The most common variation detected was a T to G transition at base pair 350, resulting in an amino acid change from a leucine to a valine. Overall, the frequencies of 350T and 350G sequences were similar (49. 4% and 50.6% respectively). Other mutations of lower frequencies were detected together with and independently of 350G. HPV-16 E6 sequence variation at base pair 350 did not correlate with HLA genotype or clinical outcome. There was no difference in the distribution of p53 proline and arginine alleles between HPV-16-positive cervical carcinoma patients and local controls, and no influence on clinical outcome; however, there was a trend for an increased frequency of p53 arginine homozygotes among the 350T carcinoma patients.
- Published
- 1999
- Full Text
- View/download PDF
35. Are there low-penetrance TP53 Alleles? evidence from childhood adrenocortical tumors.
- Author
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Varley JM, McGown G, Thorncroft M, James LA, Margison GP, Forster G, Evans DG, Harris M, Kelsey AM, and Birch JM
- Subjects
- Adaptor Proteins, Signal Transducing, Adolescent, Adrenal Cortex Neoplasms diagnosis, Adrenal Cortex Neoplasms epidemiology, Adrenal Cortex Neoplasms metabolism, Adult, Age of Onset, Aged, Carrier Proteins, Child, Child, Preschool, DNA Mutational Analysis, Female, Genetic Testing, Germ-Line Mutation genetics, Humans, Immunohistochemistry, Li-Fraumeni Syndrome genetics, Loss of Heterozygosity genetics, Male, Microsatellite Repeats genetics, Middle Aged, Molecular Sequence Data, MutL Protein Homolog 1, MutS Homolog 2 Protein, Neoplasm Proteins analysis, Nuclear Proteins, Polymorphism, Single-Stranded Conformational, Proto-Oncogene Proteins analysis, Adrenal Cortex Neoplasms genetics, Alleles, DNA-Binding Proteins, Genes, p53 genetics, Genetic Predisposition to Disease genetics, Penetrance
- Abstract
We have analyzed a panel of 14 cases of childhood adrenocortical tumors unselected for family history and have identified germline TP53 mutations in >80%, making this the highest known incidence of a germline mutation in a tumor-suppressor gene in any cancer. The spectrum of germline TP53 mutations detected is remarkably limited. Analysis of tumor tissue for loss of constitutional heterozygosity, with respect to the germline mutant allele and the occurrence of other somatic TP53 mutations, indicates complex sequences of genetic events in a number of tumors. None of the families had cancer histories that conformed to the criteria for Li-Fraumeni syndrome, but, in some families, we were able to demonstrate that the mutation had been inherited. In these families there were gene carriers unaffected in their 40s and 50s, and there were others with relatively late-onset cancers. These data provide evidence that certain TP53 alleles confer relatively low penetrance for predisposition to the development of cancer, and they imply that deleterious TP53 mutations may be more frequent in the population than has been estimated previously. Our findings have considerable implications for the clinical management of children with andrenocortical tumors and their parents, in terms of both genetic testing and the early detection and treatment of tumors.
- Published
- 1999
- Full Text
- View/download PDF
36. Highly consistent genetic alterations in childhood adrenocortical tumours detected by comparative genomic hybridization.
- Author
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James LA, Kelsey AM, Birch JM, and Varley JM
- Subjects
- Adolescent, Child, Child, Preschool, DNA, Neoplasm analysis, Female, Genes, p53, Humans, Infant, Karyotyping, Male, Mutation, Nucleic Acid Hybridization, Adenoma genetics, Adrenal Cortex Neoplasms genetics, Carcinoma genetics, Chromosome Aberrations
- Abstract
We have examined 11 cases of childhood adrenocortical tumours for copy number changes using comparative genomic hybridization (CGH). The changes seen are highly consistent between cases, and are independent of tumour type (carcinoma versus adenoma) or the presence of a germline TP53 mutation. The regions of chromosomal gain and loss identified in this study indicate the location of genes that are potentially important in the development and progression of childhood adrenocortical tumours. Finally, the copy number changes identified in childhood tumours are distinctly different to those seen in adult cases (Kjellman et al (1996) Cancer Res 56: 4219-4223), and we propose that this indicates that childhood tumours are of embryonal origin.
- Published
- 1999
- Full Text
- View/download PDF
37. Exclusion of the genes CDKN2 and PTEN as causative gene defects in Li-Fraumeni syndrome.
- Author
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Burt EC, McGown G, Thorncroft M, James LA, Birch JM, and Varley JM
- Subjects
- DNA Mutational Analysis, Genes, p53, Humans, Mutation, PTEN Phosphohydrolase, Pedigree, Genes, Tumor Suppressor genetics, Genes, p16, Li-Fraumeni Syndrome genetics, Phosphoric Monoester Hydrolases genetics, Tumor Suppressor Proteins
- Abstract
We have analysed Li-Fraumeni syndrome families, previously shown to be negative for mutations in TP53, for mutations to the tumour suppressor genes PTEN and CDKN2. These genes function in cell cycle progression or are mutated in a variety of tumours. We have detected no mutations in the family members tested.
- Published
- 1999
- Full Text
- View/download PDF
38. Radiation-induced G1 arrest is not defective in fibroblasts from Li-Fraumeni families without TP53 mutations.
- Author
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Boyle JM, Greaves MJ, Camplejohn RS, Birch JM, Roberts SA, and Varley JM
- Subjects
- Alleles, Colony-Forming Units Assay, Fibroblasts cytology, Genetic Carrier Screening, Humans, Li-Fraumeni Syndrome pathology, Mutation, Saccharomyces cerevisiae genetics, Fibroblasts radiation effects, G1 Phase radiation effects, Li-Fraumeni Syndrome genetics
- Abstract
Radiation-induced G1 arrest was studied in four classes of early passage skin fibroblasts comprising 12 normals, 12 heterozygous (mut/wt) TP53 mutation-carriers, two homozygous (mut/-) TP53 mutation-carriers and 16 strains from nine Li-Fraumeni syndrome or Li-Fraumeni-like families in which no TP53 mutation has been found, despite sequencing of all exons, exon-intron boundaries, 3' and 5' untranslated regions and promoter regions. In an assay of p53 allelic expression in yeast, cDNAs from these non-mutation strains behaved as wild-type p53. Using two different assays, we found G1 arrest was reduced in heterozygous strains with mis-sense mutations and one truncation mutation, when compared to the range established for the normal cells. Heterozygous strains with mutations at splice sites behaved like normal cells, whilst homozygous (mut/-) strains showed either extremely reduced, or no, arrest. Strains from all nine non-mutation families gave responses within the normal range. Exceptions to the previously reported inverse correlation between G1 arrest and clonogenic radiation resistance were observed, indicating that these phenotypes are not strictly interdependent.
- Published
- 1999
- Full Text
- View/download PDF
39. Isolation and characterization of a human homologue of the latrophilin gene from a region of 1p31.1 implicated in breast cancer.
- Author
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White GR, Varley JM, and Heighway J
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Cloning, Molecular, DNA, Complementary isolation & purification, Gene Expression Regulation, Neoplastic, Humans, Molecular Sequence Data, Rats, Receptors, G-Protein-Coupled, Reference Values, Sequence Analysis, Tumor Cells, Cultured, Breast Neoplasms genetics, Membrane Proteins genetics, Receptors, Peptide genetics
- Abstract
We have identified a region of chromosome 1p31.1 that shows high frequency loss of heterozygosity (LOH) in human breast cancer. This region forms part of a 7 Mb YAC/BAC contig. In order to identify candidate sequences, mutation of which might contribute to the development of disease, we have carried out mapping studies of ESTs localized to 1p31.1. This analysis, coupled with library screening and a modified 5' RACE-PCR strategy, resulted in the identification and characterization of a novel gene (LPHH1) which is located adjacent to the smallest region of overlapping loss (SRO) seen in tumours. The 4209 bp open reading frame of the 7 kb LPHH1 transcript encodes a peptide which shows approximately 65% identity to rat latrophilin, a G-coupled, seven span transmembrane protein, which binds alpha-latrotoxin. In the human sequence, whilst conservation of the transmembrane domain is high, the intra- and extracellular domains show two regions of variable structure, which are presumably generated by alternative splicing. Surprisingly, while expression of the rat gene is tightly restricted to neurological and perhaps some endocrine cells, the human sequence appears to be expressed very widely in all normal tissues tested. Northern and RT-PCR analysis of a panel of tumour cell lines showed that LPHH1 expression was variable, apparently elevated in some lines and absent or markedly reduced in others. Furthermore, characterization of the range of transcripts encoded in a breast tumour cell line, compared to normal breast, suggested that gene product variability was higher in the tumour.
- Published
- 1998
- Full Text
- View/download PDF
40. Cancer phenotype correlates with constitutional TP53 genotype in families with the Li-Fraumeni syndrome.
- Author
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Birch JM, Blair V, Kelsey AM, Evans DG, Harris M, Tricker KJ, and Varley JM
- Subjects
- Adolescent, Adult, Age Factors, Aged, Aged, 80 and over, Chi-Square Distribution, Child, Child, Preschool, Cohort Studies, DNA Mutational Analysis, Family Health, Female, Genotype, Germ-Line Mutation genetics, Humans, Infant, Infant, Newborn, Male, Middle Aged, Pedigree, Phenotype, Family, Li-Fraumeni Syndrome genetics, Neoplasms genetics, Tumor Suppressor Protein p53 genetics
- Abstract
The Li-Fraumeni cancer predisposition syndrome is associated with germline TP53 mutations in the majority of families. We have investigated cancer incidence in 34 Li-Fraumeni families, according to their constitutional TP53 mutation status. Families with germline missense mutations in the core DNA binding domain showed a more highly penetrant cancer phenotype than families with other TP53 mutations or no mutation. Cancer phenotype in families carrying such mutations was characterized by a higher cancer incidence and earlier ages at diagnosis, especially of breast cancer and brain tumours, compared with families carrying protein truncating or other inactivating mutations (P=0.03 for all cancers, P=0.006 for breast cancers, P=0.05 for brain tumours). Proband cancers showed significantly younger ages at diagnosis in those with missense mutations in the DNA binding domain than in those with protein inactivating mutations (P=0.031). In individuals with the former type of mutation, there was a significantly lower proportion of tumours which showed loss of the wild-type TP53 allele (P=0.004). These results are consistent with observations in experimental systems which demonstrate that certain mutations exhibit gain of function and/or dominant-negative properties. Our results support an enhanced oncogenic potential for such mutations in human populations.
- Published
- 1998
- Full Text
- View/download PDF
41. Genetic and functional studies of a germline TP53 splicing mutation in a Li-Fraumeni-like family.
- Author
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Varley JM, Chapman P, McGown G, Thorncroft M, White GR, Greaves MJ, Scott D, Spreadborough A, Tricker KJ, Birch JM, Evans DG, Reddel R, Camplejohn RS, Burn J, and Boyle JM
- Subjects
- Adult, Apoptosis genetics, Apoptosis physiology, Family Health, Female, Fibroblasts cytology, Fibroblasts metabolism, Germ-Line Mutation physiology, Humans, Li-Fraumeni Syndrome physiopathology, Lymphocytes cytology, Lymphocytes metabolism, Male, Pedigree, Point Mutation genetics, Point Mutation physiology, Tumor Suppressor Protein p53 physiology, Yeasts genetics, Alternative Splicing, Germ-Line Mutation genetics, Li-Fraumeni Syndrome genetics, Tumor Suppressor Protein p53 genetics
- Abstract
We report an extensive Li-Fraumeni-like family in which there is an unusual spectrum of tumours at relatively late onset. A germline TP53 splice donor mutation in exon 4 is present in all affected family members available for testing. The mutation abolishes correct splicing of intron 4 and techniques of RT-PCR have identified three different aberrant transcripts from the mutant TP53 allele. Using the yeast functional assay to analyse transcripts in cells from a number of family members with the mutant allele, TP53 appears wild-type. Functional studies have been carried out on cells from patients with and without cancer who carry the germline mutation, and on cells from unaffected individuals from the same family who do not carry the mutation. Using a number of functional endpoints known to distinguish between cells carrying mutant or wild-type TP53 alleles, we were unable to discriminate normal (wt/wt) from heterozygous (wt/mut) cells by lymphocyte apoptosis and fibroblast survival following low dose rate ionising radiation exposure. However germline mutation carriers show increased sensitivity to radiation-induced chromosome damage in the G2 phase of the cell cycle, and decreased transient and permanent G1 arrest. These studies demonstrate the importance of fully characterising the effects of TP53 germline mutations, and may explain some of the phenotypic features of this family.
- Published
- 1998
- Full Text
- View/download PDF
42. Germ-line mutations of TP53 in Li-Fraumeni families: an extended study of 39 families.
- Author
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Varley JM, McGown G, Thorncroft M, Santibanez-Koref MF, Kelsey AM, Tricker KJ, Evans DG, and Birch JM
- Subjects
- Female, Genetic Linkage, Humans, Male, Mutation, Promoter Regions, Genetic genetics, Genes, p53 genetics, Germ-Line Mutation genetics, Li-Fraumeni Syndrome genetics
- Abstract
We have previously reported on the analysis of TP53 coding mutations in 12 classic Li-Fraumeni syndrome (LFS) families plus 9 families that were Li-Fraumeni-like (LFL) families (J. M. Birch et al., Cancer Res., 54: 1298-1304, 1994). Mutations were found in 6 of 12 LFS families and in 1 of 9 LFL families. We have now extended these studies to include an additional nine LFS and nine LFL families, and TP53 mutations have been detected in eight of nine LFS families and in three of nine LFL families. Six of the new mutations described here are the same as those previously identified in other Li-Fraumeni families and are missense mutations at codons 245, 248, and 273 (in two families); a nonsense mutation at codon 209; and a mutation at the splice donor site in exon 4. The other five mutations are novel germ-line mutations and include missense mutations at codons 136 and 344, a 2-bp deletion within codon 191, a splice acceptor mutation in intron 3, and a 167-bp deletion of part of exon 1 and intron 1. In addition, we have detected a codon 175 mutation in a family previously reported as TP53 negative. To summarize all of the data from the families we have studied in this and our previous report (J. M. Birch et al., Cancer Res., 54: 1298-1304, 1994), mutations have been detected in 15 of 21 LFS families (71%) and in 4 of 18 LFL families (22%). These figures are somewhat higher than those previously reported by us and others for the frequency of TP53 mutations in LFS and LFL families. This could reflect our analysis of all 11 exons of TP53, including noncoding regions, as well as the use of direct sequencing rather than other less-sensitive mutation detection methods.
- Published
- 1997
43. Two functional assays employed to detect an unusual mutation in the oligomerisation domain of p53 in a Li-Fraumeni like family.
- Author
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Lomax ME, Barnes DM, Gilchrist R, Picksley SM, Varley JM, and Camplejohn RS
- Subjects
- Alleles, Apoptosis physiology, Codon, DNA, Complementary blood, DNA, Complementary genetics, Humans, Li-Fraumeni Syndrome blood, Li-Fraumeni Syndrome pathology, Lymphocytes physiology, Protein Structure, Tertiary, Transformation, Genetic, Tumor Suppressor Protein p53 physiology, Genes, p53, Germ-Line Mutation, Li-Fraumeni Syndrome genetics, Point Mutation, Tumor Suppressor Protein p53 genetics
- Abstract
Previous investigations of a Li - Fraumeni like family (Barnes et al., 1992) demonstrated that both the proband and her mother had elevated p53 protein levels in both tumour tissue and normal tissue at sites distant from the tumour, although no mutation was found in the p53 gene. In the present study two recently described functional assays for p53, an apoptotic assay and the functional assay for the separation of alleles in yeast (FASAY), have been employed to study the functional activity of p53 from this patient. The results of the apoptotic assay demonstrated that this patient had a p53 functional defect and the FASAY result suggested that this defect was in fact a germline mutation of the p53 gene. A point mutation of codon 337, which results in an amino acid substitution of a cysteine for an arginine, was demonstrated initially in cDNA and was confirmed by sequencing of genomic DNA. This is an unusual mutation as it is in the oligomerisation domain of p53, in contrast to the majority of p53 mutations which are in the core DNA binding domain. This mutation results in a protein which still retains partial transactivational activity in the FASAY. The mutation of codon 337 is only the second reported case of a germline missense mutation occurring in the oligomerisation domain of p53.
- Published
- 1997
- Full Text
- View/download PDF
44. Comparative genomic hybridisation of ductal carcinoma in situ of the breast: identification of regions of DNA amplification and deletion in common with invasive breast carcinoma.
- Author
-
James LA, Mitchell EL, Menasce L, and Varley JM
- Subjects
- Aged, Female, Humans, In Vitro Techniques, Middle Aged, Nucleic Acid Hybridization methods, Retrospective Studies, Breast Neoplasms genetics, Carcinoma in Situ genetics, Carcinoma, Ductal, Breast genetics, Gene Amplification genetics, Gene Deletion
- Abstract
Comparative genomic hybridisation has been used to map copy number changes in nine cases of ductal carcinoma in situ of the breast obtained from wax-embedded archive material. A wide variety of abnormalities were detected including gain of regions of 1q, 17q, 19q, 20p and 20q and loss on 13q, 14q, 17p, 16q and 22q. Amplification of areas on 10p, 8q and 20q were also observed. Chromosomal alterations were more frequent in higher grade DCIS and closely resemble those previously detected in invasive breast cancer using the same technique. These data provide strong molecular support for the view that DCIS is a precursor lesion of invasive breast carcinoma.
- Published
- 1997
- Full Text
- View/download PDF
45. Generation of a contig comprising YACs and BACs within chromosome region 1p13.1.
- Author
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Brintnell B, Hey Y, Jones D, Hoggard N, James L, and Varley JM
- Subjects
- Chromosome Mapping, Humans, In Situ Hybridization, Fluorescence, Loss of Heterozygosity, Polymerase Chain Reaction, Sequence Tagged Sites, Chromosomes, Artificial, Yeast, Chromosomes, Bacterial, Chromosomes, Human, Pair 1
- Abstract
Chromosome region 1p13 is known to show loss of heterozygosity (LOH) in a number of human tumor types, including breast. We have generated a contig comprising YACs and BACs spanning part of 1p13.1 which includes the smallest region of overlapping loss identified in our earlier studies. The contig is anchored to the genetic map by a number of microsatellite markers, and by the use of CEPH YACs. We have excluded a number of candidate genes from this region, and we have oriented the contig with respect to the centromere and a number of other genes and markers on 1p13. This resource will be valuable in mapping the target for LOH in breast and other tumors, and may also be useful for the genetic analysis of other genes or diseases known to map to this region.
- Published
- 1997
- Full Text
- View/download PDF
46. A detailed study of loss of heterozygosity on chromosome 17 in tumours from Li-Fraumeni patients carrying a mutation to the TP53 gene.
- Author
-
Varley JM, Thorncroft M, McGown G, Appleby J, Kelsey AM, Tricker KJ, Evans DG, and Birch JM
- Subjects
- Humans, Chromosome Deletion, Chromosomes, Human, Pair 17, Genes, p53, Li-Fraumeni Syndrome genetics, Mutation, Neoplasms genetics
- Abstract
We have studied a total of 36 tumours from 28 patients with germline mutations to the TP53 gene for loss of heterozygosity at TP53 using techniques of both direct sequencing and restriction fragment length polymorphism analysis. All patients were from families conforming to the definition of classical Li-Fraumeni syndrome (LFS) or were Li-Fraumeni-like (LFL). The data we have obtained show that loss of the wild-type TP53 gene is observed in under half (44%) of all tumours, and that the pattern of LOH at TP53 may be mutation specific. LOH has been observed in premalignant as well as invasive tumours. Two tumours (6%) show loss of the mutant allele and retention of the wild-type. To confirm that TP53 is indeed the target for LOH events on chromosome 17, we have used additional microsatellite repeats to examine patterns of allelic imbalance along the length of chromosome 17. Data from this analysis indicate that TP53 is the target of loss, but reveal some other interesting patterns of allelic imbalance at other loci on chromosome 17.
- Published
- 1997
- Full Text
- View/download PDF
47. Assignment of COX6A1 to 6p21 and a pseudogene (COX6A1P) to 1p31.1 by in situ hybridization and somatic cell hybrids.
- Author
-
Hey Y, Hoggard N, Burt E, James LA, and Varley JM
- Subjects
- Animals, Base Sequence, Breast Neoplasms genetics, Chromosome Mapping, Chromosomes, Artificial, Yeast genetics, DNA Primers genetics, Female, Gene Expression, Genetic Markers, Humans, Hybrid Cells, In Situ Hybridization, Molecular Sequence Data, Polymerase Chain Reaction, Chromosomes, Human, Pair 1 genetics, Chromosomes, Human, Pair 6 genetics, Electron Transport Complex IV genetics, Pseudogenes
- Published
- 1997
- Full Text
- View/download PDF
48. A novel deletion within exon 6 of TP53 in a family with Li-Fraumeni-like syndrome, and LOH in a benign lesion from a mutation carrier.
- Author
-
Varley JM, Thorncroft M, McGown G, Tricker K, Birch JM, and Evans DG
- Subjects
- Adult, Base Sequence, Child, Endometrial Neoplasms genetics, Female, Genes, p53, Heterozygote, Humans, Male, Middle Aged, Molecular Sequence Data, Pedigree, Polyps genetics, Exons genetics, Li-Fraumeni Syndrome genetics, Sequence Deletion
- Abstract
We report here a family with some of the characteristics of Li-Fraumeni syndrome (Li-Fraumeni-like) in which there is a 2 base pair deletion within exon 6 of TP53 in two affected individuals. Of particular interest in this family is a study of loss of heterozygosity (LOH) of the TP53 gene, and the finding that there is LOH in all cancers available for study from mutation carriers, and additionally from a benign endometrial polyp from one of those patients. Two other family members, one with a rectal carcinoma aged 55, the other with two separate benign lesions under the age of 45, were both wild-type for the TP53 mutation.
- Published
- 1996
- Full Text
- View/download PDF
49. A previously undescribed mutation within the tetramerisation domain of TP53 in a family with Li-Fraumeni syndrome.
- Author
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Varley JM, McGown G, Thorncroft M, Cochrane S, Morrison P, Woll P, Kelsey AM, Mitchell EL, Boyle J, Birch JM, and Evans DG
- Subjects
- Adult, Alleles, Base Sequence, Female, Genotype, Humans, Karyotyping, Male, Molecular Sequence Data, Pedigree, Sequence Analysis, DNA, Codon genetics, Genes, p53 genetics, Li-Fraumeni Syndrome genetics, Point Mutation genetics
- Abstract
We report details of a family with classic Li-Fraumeni syndrome in which there is a mutation in codon 344 of the tumour suppressor gene TP53. Codon 344 is a key residue within the tetramerisation domain, and the amino acid substitution of a proline for a leucine is predicted to have profound implications for tetramerisation and potentially DNA binding. This is the first report of a mutation at this residue in either sporadic tumours or in the germline and the first report of a germline mutation within the tetramerisation domain. The family does not appear to be remarkable in the spectrum of tumours, and there is loss of the wild-type allele in a leiomyosarcoma from the proband. A cell line has been established from the tumour of the proband and cytogenetic and molecular studies carried out, providing an extensive analysis in this family.
- Published
- 1996
50. An extended Li-Fraumeni kindred with gastric carcinoma and a codon 175 mutation in TP53.
- Author
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Varley JM, McGown G, Thorncroft M, Tricker KJ, Teare MD, Santibanez-Koref MF, Martin J, Birch JM, and Evans DG
- Subjects
- Codon, Female, Humans, Male, Mutation, Pedigree, Gastrointestinal Neoplasms genetics, Genes, p53, Li-Fraumeni Syndrome genetics
- Abstract
We present an extended family with Li-Fraumeni syndrome characterised by gastric and breast carcinoma, glioma, sarcoma, and leukaemia. This family showed strong evidence of linkage to TP53, and three of four tumours analysed showed loss of the wild type allele. A codon 175 missense mutation was identified in exon 5 in all available affected subjects. Counselling, screening, and issues surrounding presymptomatic testing are discussed.
- Published
- 1995
- Full Text
- View/download PDF
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