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1.
Anaesthesia ; 77(1): 96-104, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34494667

RESUMO

The decision-to-delivery interval is a widely used term at non-elective caesarean section. While the definition may appear self-evident, there is no universally agreed consensus about when this period begins and ends. We reviewed the literature for original research utilising the terms 'decision-to-delivery', 'decision-to-incision' or 'incision-to-delivery' and examined definitions used for decision, delivery, incision, as well as any additional time intervals that were assessed. Our analysis demonstrated an inconsistent non-standardised approach to defining these intervals, which might have clinical practice and medicolegal ramifications. We propose that the decision-to-delivery interval should be defined as follows: the interval between the time at which the senior obstetrician makes the decision that a caesarean section is required and the time at which the fetus (or first fetus in the case of multiples) is delivered. The decision time should ideally be recorded contemporaneously in the medical notes or partogram.


Assuntos
Cesárea/normas , Tomada de Decisões , Feminino , Humanos , Gravidez , Fatores de Tempo
3.
Ann Oncol ; 31(11): 1518-1525, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32798689

RESUMO

BACKGROUND: Cisplatin and paclitaxel are active in triple-negative breast cancer (TNBC). Despite different mechanisms of action, effective predictive biomarkers to preferentially inform drug selection have not been identified. The homologous recombination deficiency (HRD) assay (Myriad Genetics, Inc.) detects impaired double-strand DNA break repair and may identify patients with BRCA1/2-proficient tumors that are sensitive to DNA-targeting therapy. The primary objective of TBCRC 030 was to detect an association of HRD with pathologic response [residual cancer burden (RCB)-0/1] to single-agent cisplatin or paclitaxel. PATIENTS AND METHODS: This prospective phase II study enrolled patients with germline BRCA1/2 wild-type/unknown stage I-III TNBC in a 12-week randomized study of preoperative cisplatin or paclitaxel. The HRD assay was carried out on baseline tissue; positive HRD was defined as a score ≥33. Crossover to an alternative chemotherapy was offered if there was inadequate response. RESULTS: One hundred and thirty-nine patients were evaluable for response, including 88 (63.3%) who had surgery at 12 weeks and 51 (36.7%) who crossed over to an alternative provider-selected preoperative chemotherapy regimen due to inadequate clinical response. HRD results were available for 104 tumors (74.8%) and 74 (71.1%) were HRD positive. The RCB-0/1 rate was 26.4% with cisplatin and 22.3% with paclitaxel. No significant association was observed between HRD score and RCB response to either cisplatin [odds ratio (OR) for RCB-0/1 if HRD positive 2.22 (95% CI: 0.39-23.68)] or paclitaxel [OR for RCB-0/1 if HRD positive 0.90 (95% CI: 0.19-4.95)]. There was no evidence of an interaction between HRD and pathologic response to chemotherapy. CONCLUSIONS: In this prospective preoperative trial in TNBC, HRD was not predictive of pathologic response. Tumors were similarly responsive to preoperative paclitaxel or cisplatin chemotherapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias de Mama Triplo Negativas , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores , Cisplatino/uso terapêutico , Recombinação Homóloga , Humanos , Mutação , Terapia Neoadjuvante , Paclitaxel/uso terapêutico , Estudos Prospectivos , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética
4.
BJOG ; 127(4): 458-465, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31715078

RESUMO

OBJECTIVE: To determine whether socioeconomic deprivation affects IVF outcome independent of the number of cycles undertaken. DESIGN: A retrospective review of prospectively collected data. SETTING: A tertiary level fertility clinic in the North of England. POPULATION: All participants undergoing their first fresh single-embryo transfer, funded by the National Health Service (NHS), between January 2012 and December 2017. METHODS: For each case, identified from the clinic database, we recorded the following: age; body mass index; FSH; number of eggs retrieved; ethnicity; cause of subfertility; stage of embryo transfer; and whether any adjuncts i.e. EmbryoGlue® or Time Lapse Imaging were used. Socio-economic deprivation was assessed using the Index of Multiple Deprivation (IMD) determined by the residential postcode. MAIN OUTCOME MEASURES: Clinical pregnancy (CP) and live birth (LB) rates across IMD quintiles. RESULTS: Three thousand ninety-one women were included. Overall, CP and LB rates were 35.9% and 31.3% respectively. CP rates increased significantly from 31.0% in the most deprived group to 38.8% in the least deprived group (P < 0.01). Similarly, LB rates were significantly lower in the most deprived group compared with the least deprived group (26.8 versus 35.4%, P < 0.01). After adjusting for confounding variables, women in the least deprived group were significantly more likely to have a LB (aRR 1.18, 95% CI 1.00-1.39) than women in the most deprived group. CONCLUSIONS: More socio-economically deprived patients are significantly less likely to achieve a LB than less deprived patients independent of the number of cycles of IVF undertaken. TWEETABLE ABSTRACT: More deprived patients are less likely to have a LB per cycle of IVF than less deprived patients.


Assuntos
Fertilização in vitro/estatística & dados numéricos , Disparidades nos Níveis de Saúde , Nascido Vivo/epidemiologia , Taxa de Gravidez , Adulto , Inglaterra/epidemiologia , Feminino , Humanos , Gravidez , Estudos Retrospectivos , Fatores Socioeconômicos , Medicina Estatal
5.
Ann Oncol ; 29(4): 903-909, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29452344

RESUMO

Background: Platinum-based therapy is an effective treatment for a subset of triple-negative breast cancer and ovarian cancer patients. In order to increase response rate and decrease unnecessary use, robust biomarkers that predict response to therapy are needed. Patients and methods: We performed an integrated genomic approach combining differential analysis of gene expression and DNA copy number in sensitive compared with resistant triple-negative breast cancers in two independent neoadjuvant cisplatin-treated cohorts. Functional relevance of significant hits was investigated in vitro by overexpression, knockdown and targeted inhibitor treatment. Results: We identified two genes, the Bloom helicase (BLM) and Fanconi anemia complementation group I (FANCI), that have both increased DNA copy number and gene expression in the platinum-sensitive cases. Increased level of expression of these two genes was also associated with platinum but not with taxane response in ovarian cancer. As a functional validation, we found that overexpression of BLM promotes DNA damage and induces sensitivity to cisplatin but has no effect on paclitaxel sensitivity. Conclusions: A biomarker based on the expression levels of the BLM and FANCI genes is a potential predictor of platinum sensitivity in triple-negative breast cancer and ovarian cancer.


Assuntos
Antineoplásicos/uso terapêutico , Dano ao DNA , Neoplasias Ovarianas/metabolismo , Compostos de Platina/uso terapêutico , RecQ Helicases/fisiologia , Neoplasias de Mama Triplo Negativas/metabolismo , Feminino , Humanos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/patologia
7.
Oncogene ; 36(12): 1707-1720, 2017 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-27694895

RESUMO

Tumours are comprised of a highly heterogeneous population of cells, of which only a small subset of stem-like cells possess the ability to regenerate tumours in vivo. These cancer stem cells (CSCs) represent a significant clinical challenge as they are resistant to conventional cancer therapies and play essential roles in metastasis and tumour relapse. Despite this realization and great interest in CSCs, it has been difficult to develop CSC-targeted treatments due to our limited understanding of CSC biology. Here, we present evidence that specific histone deacetylases (HDACs) play essential roles in the CSC phenotype. Utilizing a novel CSC model, we discovered that the HDACs, HDAC1 and HDAC7, are specifically over-expressed in CSCs when compared to non-stem-tumour-cells (nsTCs). Furthermore, we determine that HDAC1 and HDAC7 are necessary to maintain CSCs, and that over-expression of HDAC7 is sufficient to augment the CSC phenotype. We also demonstrate that clinically available HDAC inhibitors (HDACi) targeting HDAC1 and HDAC7 can be used to preferentially target CSCs. These results provide actionable insights that can be rapidly translated into CSC-specific therapies.


Assuntos
Neoplasias da Mama/metabolismo , Histona Desacetilase 1/metabolismo , Histona Desacetilases/metabolismo , Células-Tronco Neoplásicas/metabolismo , Neoplasias Ovarianas/metabolismo , Animais , Biomarcadores , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Modelos Animais de Doenças , Descoberta de Drogas , Feminino , Técnicas de Silenciamento de Genes , Genes Letais , Xenoenxertos , Histona Desacetilase 1/genética , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/genética , Humanos , Camundongos , Células-Tronco Neoplásicas/efeitos dos fármacos , Neoplasias Ovarianas/genética , Fenótipo , RNA Interferente Pequeno/genética
8.
Oncogene ; 36(6): 746-755, 2017 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-27452521

RESUMO

Loss-of-function mutations in the BRCA1 and BRCA2 genes increase the risk of cancer. Owing to their function in homologous recombination repair, much research has focused on the unstable genomic phenotype of BRCA1/2 mutant cells manifest mainly as large-scale rearrangements. We used whole-genome sequencing of multiple isogenic chicken DT40 cell clones to precisely determine the consequences of BRCA1/2 loss on all types of genomic mutagenesis. Spontaneous base substitution mutation rates increased sevenfold upon the disruption of either BRCA1 or BRCA2, and the arising mutation spectra showed strong and specific correlation with a mutation signature associated with BRCA1/2 mutant tumours. To model endogenous alkylating damage, we determined the mutation spectrum caused by methyl methanesulfonate (MMS), and showed that MMS also induces more base substitution mutations in BRCA1/2-deficient cells. Spontaneously arising and MMS-induced insertion/deletion mutations and large rearrangements were also more common in BRCA1/2 mutant cells compared with the wild-type control. A difference in the short deletion phenotypes of BRCA1 and BRCA2 suggested distinct roles for the two proteins in the processing of DNA lesions, as BRCA2 mutants contained more short deletions, with a wider size distribution, which frequently showed microhomology near the breakpoints resembling repair by non-homologous end joining. An increased and prolonged gamma-H2AX signal in MMS-treated BRCA1/2 cells suggested an aberrant processing of stalled replication forks as the cause of increased mutagenesis. The high rate of base substitution mutagenesis demonstrated by our experiments is likely to significantly contribute to the oncogenic effect of the inactivation of BRCA1 or BRCA2.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Animais , Proteína BRCA1/efeitos dos fármacos , Proteína BRCA2/deficiência , Galinhas , Feminino , Genômica/métodos , Humanos , Masculino , Mutagênese
9.
Ann Oncol ; 26(2): 259-71, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25214542

RESUMO

BACKGROUND: The morphological evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer (BC) is gaining momentum as evidence strengthens for the clinical relevance of this immunological biomarker. Accumulating evidence suggests that the extent of lymphocytic infiltration in tumor tissue can be assessed as a major parameter by evaluation of hematoxylin and eosin (H&E)-stained tumor sections. TILs have been shown to provide prognostic and potentially predictive value, particularly in triple-negative and human epidermal growth factor receptor 2-overexpressing BC. DESIGN: A standardized methodology for evaluating TILs is now needed as a prerequisite for integrating this parameter in standard histopathological practice, in a research setting as well as in clinical trials. This article reviews current data on the clinical validity and utility of TILs in BC in an effort to foster better knowledge and insight in this rapidly evolving field, and to develop a standardized methodology for visual assessment on H&E sections, acknowledging the future potential of molecular/multiplexed approaches. CONCLUSIONS: The methodology provided is sufficiently detailed to offer a uniformly applied, pragmatic starting point and improve consistency and reproducibility in the measurement of TILs for future studies.


Assuntos
Neoplasias da Mama/imunologia , Linfócitos do Interstício Tumoral , Feminino , Humanos
10.
Artigo em Inglês | MEDLINE | ID: mdl-16869742

RESUMO

As a clinical entity, breast cancer appears to be a series of subforms, each with a relatively specific molecular phenotype. Among the characteristics that differentiate these subforms are sex hormone receptor expression, HER2 expression, p53 mutation, high-grade histopathology, and particular gene expression array patterns. Sporadic basal-like breast cancer is one such form. It is a relatively common, high-grade, hormone receptor and HER2-expression-negative, p53 mutation-bearing tumor and is particularly lethal. Although wild type for BRCA1, it is a sporadic phenocopy of most cases of BRCA1(/) breast cancer. Not only do the cells of the two tumors resemble one another with respect to the above-noted characteristics, they also share a defect in the maintenance of an intact, inactive X chromosome (Xi). Other high-grade and most low-grade tumors are rarely defective at Xi. This evidence suggests that an Xi defect contributes to the evolution of both sporadic and BRCA1(/) basal-like breast tumors.


Assuntos
Neoplasias da Mama/genética , Cromossomos Humanos X/genética , Genes BRCA1 , Inativação do Cromossomo X , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Mutação em Linhagem Germinativa , Heterocromatina/genética , Humanos , Neoplasia de Células Basais/genética , Neoplasia de Células Basais/patologia
12.
Eur J Endocrinol ; 146(5): 619-27, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-11980616

RESUMO

OBJECTIVE: The aim of this study was to determine the primary genetic events that may underlie the formation of parathyroid tumors in patients with lithium-associated hyperparathyroidism (HPT). METHODS: Comparative genomic hybridization (CGH), loss of heterozygosity (LOH) and multiple endocrine neoplasia type 1 gene (MEN1) mutation analysis were used to analyze twelve parathyroid tumors from nine patients with lithium-associated HPT. For comparison, CGH was also carried out in a non-lithium-associated group of thirteen sporadic parathyroid tumors. RESULTS: A higher prevalence of multiglandular disease in the lithium-associated HPT patients compared with the idiopathic sporadic patients was observed (Fisher's exact test, P=0.02). CGH alterations were detected in four lithium-associated parathyroid tumors, involving loss at 1p, 11, 15q, 22q and gain of the X chromosome. In addition, one of these four cases exhibited LOH at 11q13 and was found to contain a novel somatic MEN1 mutation (c.1193insTAC). Although fewer lithium-associated parathyroid tumors were shown to contain genetic alterations compared with the sporadic parathyroid tumors, the changes detected were those frequently associated with both familial and sporadic parathyroid tumorigenesis. CONCLUSION: This is, to our knowledge, the first genetic analysis of parathyroid tumors in lithium-associated HPT patients. Our data indicated that the majority of lithium-associated parathyroid tumors do not contain gross chromosomal alterations and suggest that in most cases the tumorigenic pathway is independent of MEN1 and genes at 1p34.3-pter and 1q21-q32. It is possible that other discrete genetic alterations or epigenetic changes, not screened for in this study, could also be responsible for parathyroid tumorigenesis in lithium-associated HPT.


Assuntos
Lítio/efeitos adversos , Neoplasias das Paratireoides/induzido quimicamente , Neoplasias das Paratireoides/genética , Proteínas Proto-Oncogênicas , Adolescente , Adulto , Idoso , Cromossomos Humanos Par 1/genética , Cromossomos Humanos Par 11/genética , Análise Mutacional de DNA , Feminino , Humanos , Hiperparatireoidismo/induzido quimicamente , Perda de Heterozigosidade , Masculino , Pessoa de Meia-Idade , Neoplasia Endócrina Múltipla/epidemiologia , Proteínas de Neoplasias/genética , Hibridização de Ácido Nucleico , Neoplasias das Paratireoides/epidemiologia , Prevalência
14.
Neoplasia ; 3(3): 236-44, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11494117

RESUMO

Germline mutations in tumor suppressor genes, or less frequently oncogenes, have been identified in up to 19 familial cancer syndromes including Li-Fraumeni syndrome, familial paraganglioma, familial adenomatous polyposis coli and breast and ovarian cancers. Multiple genes have been associated with some syndromes as approximately 26 genes have been linked to the development of these familial cancers. With this increased knowledge of the molecular determinants of familial cancer comes an equal expectation for efficient genetic screening programs. We have trialled denaturing high-performance liquid chromatography (dHPLC) as a tool for rapid germline mutation scanning of genes implicated in three familial cancer syndromes -- Cowden syndrome (PTEN mutation), multiple endocrine neoplasia type 2 (RET mutation) and von Hippel-Lindau disease (VHL mutation). Thirty-two mutations, including 21 in PTEN, 9 in RET plus a polymorphism, and 2 in VHL, were analyzed using the WAVE DNA fragment analysis system with 100% detection efficiency. In the case of the tumor suppressor gene PTEN, mutations were scattered along most of the gene. However, mutations in the RET proto-oncogene associated with multiple endocrine neoplasia type 2 were limited to specific clusters or "hot spots." The use of GC-clamped primers to scan for mutations scattered along PTEN exons was shown to greatly enhance the sensitivity of detection of mutant hetero- and homoduplex peaks at a single denaturation temperature compared to fragments generated using non--GC-clamped primers. Thus, when scanning tumor suppressor genes for germline mutation using dHPLC, the incorporation of appropriate GC-clamped primers will likely increase the efficiency of mutation detection.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Mutação em Linhagem Germinativa/genética , Síndromes Neoplásicas Hereditárias/genética , Genes Supressores de Tumor , Síndrome do Hamartoma Múltiplo/genética , Síndrome do Hamartoma Múltiplo/patologia , Humanos , Neoplasia Endócrina Múltipla/genética , Neoplasia Endócrina Múltipla/patologia , Desnaturação de Ácido Nucleico , Fenótipo , Reação em Cadeia da Polimerase , Proto-Oncogene Mas , Temperatura , Doença de von Hippel-Lindau/genética , Doença de von Hippel-Lindau/patologia
15.
J Med Genet ; 38(3): 159-64, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11238682

RESUMO

Cowden syndrome (CS) (OMIM 158350) is a multiple hamartoma syndrome associated with germline mutations in the PTEN tumour suppressor gene. While CS is characterised most commonly by non-cancerous lesions (mucocutaneous trichilemmomas, acral and palmoplantar keratoses, and papillomatous papules), it is also associated with an increased susceptibility to breast cancer (in females) and thyroid cancer, as well as non-cancerous conditions of the breast and thyroid. Here we report two cases of male breast cancer occurring in patients with classical CS phenotypes and germline PTEN mutations. The first subject was diagnosed with CS indicated primarily by mucocutaneous papillomatosis, facial trichilemmomas, and macrocephaly with frontal bossing at the age of 31 years. He developed breast cancer at 41 years and subsequently died of the disease. A PTEN mutation, c.802delG, was identified in this subject, yet none of his family members showed evidence of a CS phenotype, suggesting that this PTEN mutation may be a de novo occurrence. The second subject had a CS phenotype including multiple trichilemmomas and thyroid adenoma, developed male breast cancer at 43 years, and died of the disease at 57 years. He was a carrier of a PTEN mutation c.347-351delACAAT that cosegregated with the CS phenotype in affected family members. These two cases of male breast cancer associated with germline PTEN mutations and the CS phenotype suggest that CS may be associated with an increased risk of early onset male as well as female breast cancer.


Assuntos
Neoplasias da Mama Masculina/genética , Mutação em Linhagem Germinativa , Síndrome do Hamartoma Múltiplo/genética , Monoéster Fosfórico Hidrolases/genética , Proteínas Supressoras de Tumor , Adulto , Idoso , Neoplasias da Mama/genética , Neoplasias da Mama Masculina/complicações , Neoplasias da Mama Masculina/patologia , DNA/química , DNA/genética , Análise Mutacional de DNA , Saúde da Família , Evolução Fatal , Feminino , Síndrome do Hamartoma Múltiplo/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , PTEN Fosfo-Hidrolase , Linhagem
16.
Clin Endocrinol (Oxf) ; 53(1): 85-92, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10931084

RESUMO

OBJECTIVE: Hyperparathyroidism (HPT) is a common endocrine disorder. Several loci of genetic interest have been identified in parathyroid tumours, including the MEN1 gene locus at 11q13; the HPT-JT region at 1q21-q32; and a putative tumour suppressor gene on 1p. We analysed these intervals, which harbour known genes or putative loci associated with familial hyperparathyroidism, in order to clarify the involvement of the respective regions in parathyroid tumourigenesis. DESIGN: We performed loss of heterozygosity (LOH) studies on 33 sporadic parathyroid tumours using a PCR based technique. A total of 22 microsatellite markers were used to analyse loci at 11q13, 1q21-q32 and 1p. Ten markers located distal on 1p, eight markers encompassed the HPT-JT region at 1q21-q32 and four markers surrounded the MEN1 gene locus at 11q13. MEN1 mutations were screened for using Single Strand Conformation Polymorphism analysis (SSCP) and automated sequencing of SSCP variants. PATIENTS: Thirty-three parathyroid glands and the corresponding blood samples were obtained from 33 patients (26 females and seven males) who underwent parathyroidectomy for primary hyperparathyroidism. RESULTS: Loss of heterozygosity was detected in 13 of 33 (39%) cases at 11q13, 6 of 33 (18%) cases at 1p, and in three of 33 (9%) cases at 1q (in conjunction with 1p loss). Only one of the 18 tumours in which LOH was detected, showed LOH at both chromosome 1 and chromosome 11. Additionally, those tumours found to exhibit LOH at 11q13 were screened for MEN1 mutations using single strand conformation polymorphism analysis (SSCP) and automated sequencing. Nine novel somatic mutations were found on the remaining allele in 13 (69%) tumours. CONCLUSIONS: This study consolidates the role of multiple loci in the pathogenesis of sporadic parathyroid tumours. The results indicate that there are at least two genetic loci involved in sporadic parathyroid tumourigenesis on chromosome 1, one of which has been linked to the distinct familial parathyroid condition, hyperparathyroidism-jaw tumour (HPT-JT) syndrome. The high frequency of loss of heterozygosity at 1p suggests the presence of a tumour suppressor at this locus.


Assuntos
Adenoma/genética , Cromossomos Humanos Par 11/genética , Cromossomos Humanos Par 1/genética , Perda de Heterozigosidade , Proteínas de Neoplasias/genética , Neoplasias das Paratireoides/genética , Proteínas Proto-Oncogênicas , Feminino , Humanos , Masculino , Neoplasia Endócrina Múltipla Tipo 1/genética , Mutação , Polimorfismo Conformacional de Fita Simples
17.
Cancer Res ; 60(24): 7048-51, 2000 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-11156410

RESUMO

Pheochromocytomas are tumors of the adrenal medulla originating in the chromaffin cells derived from the neural crest. Ten % of these tumors are associated with the familial cancer syndromes multiple endocrine neoplasia type 2, von Hippel-Lindau disease (VHL), and rarely, neurofibromatosis type 1, in which germ-line mutations have been identified in RET, VHL, and NF1, respectively. In both the sporadic and familial form of pheochromocytoma, allelic loss at 1p, 3p, 17p, and 22q has been reported, yet the molecular pathogenesis of these tumors is largely unknown. Allelic loss at chromosome 1p has also been reported in other endocrine tumors, such as medullary thyroid cancer and tumors of the parathyroid gland, as well as in tumors of neural crest origin including neuroblastoma and malignant melanoma. In this study, we performed fine structure mapping of deletions at chromosome 1p in familial and sporadic pheochromocytomas to identify discrete regions likely housing tumor suppressor genes involved in the development of these tumors. Ten microsatellite markers spanning a region of approximately 70 cM (1pter to 1p34.3) were used to screen 20 pheochromocytomas from 19 unrelated patients for loss of heterozygosity (LOH). LOH was detected at five or more loci in 8 of 13 (61%) sporadic samples and at five or more loci in four of five (80%) tumor samples from patients with multiple endocrine neoplasia type 2. No LOH at 1p was detected in pheochromocytomas from two VHL patients. Analysis of the combined sporadic and familial tumor data suggested three possible regions of common somatic loss, designated as PC1 (D1S243 to D1S244), PC2 (D1S228 to D1S507), and PC3 (D1S507 toward the centromere). We propose that chromosome 1p may be the site of at least three putative tumor suppressor loci involved in the tumorigenesis of pheochromocytomas. At least one of these loci, PC2 spanning an interval of <3.8 cM, is likely to have a broader role in the development of endocrine malignancies.


Assuntos
Neoplasias das Glândulas Suprarrenais/genética , Deleção Cromossômica , Cromossomos Humanos Par 1 , Proteínas de Drosophila , Feocromocitoma/genética , Adolescente , Adulto , Idoso , Alelos , Mapeamento Cromossômico , Saúde da Família , Feminino , Mutação em Linhagem Germinativa , Humanos , Perda de Heterozigosidade , Masculino , Repetições de Microssatélites , Pessoa de Meia-Idade , Modelos Genéticos , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-ret , Receptores Proteína Tirosina Quinases/genética
18.
Hum Mol Genet ; 7(3): 507-15, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9467011

RESUMO

The tumour suppressor gene PTEN , which maps to 10q23.3 and encodes a 403 amino acid dual specificity phosphatase (protein tyrosine phosphatase; PTPase), was shown recently to play a broad role in human malignancy. Somatic PTEN deletions and mutations were observed in sporadic breast, brain, prostate and kidney cancer cell lines and in several primary tumours such as endometrial carcinomas, malignant melanoma and thyroid tumours. In addition, PTEN was identified as the susceptibility gene for two hamartoma syndromes: Cowden disease (CD; MIM 158350) and Bannayan-Zonana (BZS) or Ruvalcaba-Riley-Smith syndrome (MIM 153480). Constitutive DNA from 37 CD families and seven BZS families was screened for germline PTEN mutations. PTEN mutations were identified in 30 of 37 (81%) CD families, including missense and nonsense point mutations, deletions, insertions, a deletion/insertion and splice site mutations. These mutations were scattered over the entire length of PTEN , with the exception of the first, fourth and last exons. A 'hot spot' for PTEN mutation in CD was identified in exon 5 that contains the PTPase core motif, with 13 of 30 (43%) CD mutations identified in this exon. Seven of 30 (23%) were within the core motif, the majority (five of seven) of which were missense mutations, possibly pointing to the functional significance of this region. Germline PTEN mutations were identified in four of seven (57%) BZS families studied. Interestingly, none of these mutations was observed in the PTPase core motif. It is also worthy of note that a single nonsense point mutation, R233X, was observed in the germline DNA from two unrelated CD families and one BZS family. Genotype-phenotype studies were not performed on this small group of BZS families. However, genotype-phenotype analysis inthe group of CD families revealed two possible associations worthy of follow-up in independent analyses. The first was an association noted in the group of CD families with breast disease. A correlation was observed between the presence/absence of a PTEN mutation and the type of breast involvement (unaffected versus benign versus malignant). Specifically and more directly, an association was also observed between the presence of a PTEN mutation and malignant breast disease. Secondly, there appeared to be an interdependent association between mutations upstream and within the PTPase core motif, the core motif containing the majority of missense mutations, and the involvement of all major organ systems (central nervous system, thyroid, breast, skin and gastrointestinal tract). However, these observations would need to be confirmed by studying a larger number of CD families.


Assuntos
Cromossomos Humanos Par 10 , Genes Supressores de Tumor , Mutação em Linhagem Germinativa , Síndrome do Hamartoma Múltiplo/genética , Monoéster Fosfórico Hidrolases , Proteínas Tirosina Fosfatases/genética , Proteínas Supressoras de Tumor , Mapeamento Cromossômico , Éxons , Feminino , Genótipo , Humanos , Masculino , PTEN Fosfo-Hidrolase , Fenótipo , Síndrome , Células Tumorais Cultivadas
19.
Genes Chromosomes Cancer ; 21(1): 61-9, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9443042

RESUMO

Cowden disease (CD) is a rare, autosomal dominant inherited cancer syndrome characterized by multiple benign and malignant lesions in a wide spectrum of tissues. While individuals with CD have an increased risk of breast and thyroid neoplasms, the primary features of CD are hamartomas. The gene for CD has been mapped by linkage analysis to a 6 cM region on the long arm of chromosome 10 at 10q22-23. Loss of heterozygosity (LOH) studies of sporadic follicular thyroid adenomas and carcinomas, both component tumors of CD, have suggested that the putative susceptibility gene for CD is a tumor suppressor gene. Somatic missense and nonsense mutations have recently been identified in breast, prostate, and brain tumor cell lines in a gene encoding a dual specificity phosphatase, PTEN/MMACI, mapped at 10q23.3. Furthermore, germline PTEN/MMACI mutations are associated with CD. In the present study, 20 hamartomas from 11 individuals belonging to ten unrelated families with CD have been examined for LOH of markers flanking and within PTEN/MMACI. Eight of these ten families have germline PTEN/MMACI mutations. LOH involving microsatellite markers within the CD interval, and including PTEN/MMACI, was identified in two fibroadenomas of the breast, a thyroid adenoma, and a pulmonary hamartoma belonging to 3 to 11 (27%) of these patients. The wild-type allele was lost in these hamartomas. Semi-quantitative PCR performed on RNA from hamartomas from three different tissues from a CD patient suggested substantial reduction of PTEN/MMACI RNA levels in all of these tissues. The LOH identified in samples from individuals with CD and the suggestion of allelic loss and reduced transcription in hamartomas from a CD patient provide evidence that PTEN/MMACI functions as a tumor suppressor in CD.


Assuntos
Cromossomos Humanos Par 10/genética , Deleção de Genes , Mutação em Linhagem Germinativa , Síndrome do Hamartoma Múltiplo/genética , Monoéster Fosfórico Hidrolases , Proteínas Tirosina Fosfatases/genética , Proteínas Supressoras de Tumor , Feminino , Haplótipos , Humanos , Perda de Heterozigosidade/genética , Masculino , PTEN Fosfo-Hidrolase , Linhagem
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