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1.
ESMO Open ; 9(3): 102923, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38452438

RESUMO

BACKGROUND: In the absence of prognostic biomarkers, most patients with early-stage triple-negative breast cancer (eTNBC) are treated with combination chemotherapy. The identification of biomarkers to select patients for whom treatment de-escalation or escalation could be considered remains an unmet need. We evaluated the prognostic value of histopathologic traits in a unique cohort of young, (neo)adjuvant chemotherapy-naïve patients with early-stage (stage I or II), node-negative TNBC and long-term follow-up, in relation to stromal tumor-infiltrating lymphocytes (sTILs) for which the prognostic value was recently reported. MATERIALS AND METHODS: We studied all 485 patients with node-negative eTNBC from the population-based PARADIGM cohort which selected women aged <40 years diagnosed between 1989 and 2000. None of the patients had received (neo)adjuvant chemotherapy according to standard practice at the time. Associations between histopathologic traits and breast cancer-specific survival (BCSS) were analyzed with Cox proportional hazard models. RESULTS: With a median follow-up of 20.0 years, an independent prognostic value for BCSS was observed for lymphovascular invasion (LVI) [adjusted (adj.) hazard ratio (HR) 2.35, 95% confidence interval (CI) 1.49-3.69], fibrotic focus (adj. HR 1.61, 95% CI 1.09-2.37) and sTILs (per 10% increment adj. HR 0.75, 95% CI 0.69-0.82). In the sTILs <30% subgroup, the presence of LVI resulted in a higher cumulative incidence of breast cancer death (at 20 years, 58%; 95% CI 41% to 72%) compared with when LVI was absent (at 20 years, 32%; 95% CI 26% to 39%). In the ≥75% sTILs subgroup, the presence of LVI might be associated with poor survival (HR 11.45, 95% CI 0.71-182.36, two deaths). We confirm the lack of prognostic value of androgen receptor expression and human epidermal growth factor receptor 2 -low status. CONCLUSIONS: sTILs, LVI and fibrotic focus provide independent prognostic information in young women with node-negative eTNBC. Our results are of importance for the selection of patients for de-escalation and escalation trials.


Assuntos
Neoplasias de Mama Triplo Negativas , Humanos , Feminino , Prognóstico , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/patologia , Linfócitos do Interstício Tumoral/metabolismo , Linfócitos do Interstício Tumoral/patologia , Biomarcadores Tumorais , Quimioterapia Adjuvante
2.
Clin Genitourin Cancer ; 22(2): 445-453.e1, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38246830

RESUMO

BACKGROUND: There is new interest in platinum-based treatment of patients with metastatic castration resistant prostate cancer (mCRPC), to which a subgroup responds. Although platinum sensitivity is suggested to be associated with aggressive disease features and distinct molecular profiles, identification of responders is a clinical challenge. In this study, we selected patients who displayed PSA progression during cabazitaxel monotherapy, for combined cabazitaxel and carboplatin treatment. METHODS: In this retrospective study, mCRPC patients received carboplatin and cabazitaxel after biochemical progression following at least 2 cabazitaxel monotherapy cycles. We assessed PSA response, Time to PSA Progression (TTpsa) and Time to Radiographic Progression (TTrad). For a subset of patients, mutational analysis of BRCA-1, BRCA-2, ATM, PTEN, P53 and RB1 was performed. RESULTS: Forty-five patients were included, after a median of 4 (3-6) cycles of cabazitaxel monotherapy. Patients received a median of 3 (2-5) cycles of combined cabazitaxel and carboplatin, on which 12 (26.6%) patients had a PSA decline ≥ 50% from baseline. TTpsa was 2 (1-5) months and TTrad 3 (2-6) months. Adverse events were predominantly grade 1-2. Of the 29 (64.4%) patients evaluable for molecular signature, 6 (13.3%) had BRCA1, BRCA2 or ATM mutations and 12 (26.7%) had a PTEN, P53 or RB1 mutations. The occurrence of these mutations was not associated with any clinical outcome measure. CONCLUSIONS: In this study we showed that patients with PSA progression during cabazitaxel monotherapy could benefit from the addition of carboplatin to cabazitaxel, while prospective identification of these patients remains a clinical challenge.


Assuntos
Neoplasias de Próstata Resistentes à Castração , Taxoides , Masculino , Humanos , Carboplatina/uso terapêutico , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , Antígeno Prostático Específico , Resultado do Tratamento , Estudos Retrospectivos , Estudos Prospectivos , Proteína Supressora de Tumor p53/genética , Intervalo Livre de Doença , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico
3.
Cancer Immunol Immunother ; 73(2): 28, 2024 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-38280045

RESUMO

INTRODUCTION: Immune checkpoint inhibition (ICI) has improved patients' outcomes in advanced melanoma, often resulting in durable response. However, not all patients have durable responses and the patients with dissociated response are a valuable subgroup to identify mechanisms of ICI resistance. METHODS: Stage IV melanoma patients treated with ICI and dissociated response were retrospectively screened for available samples containing sufficient tumor at least at two time-points. Included were one patient with metachronous regressive and progressive lesions at the same site, two patients with regressive and novel lesion at different sites, and three patients with regressive and progressive lesions at different sites. In addition, four patients with acquired resistant tumor samples without a matched second sample were included. RESULTS: In the majority of patients, the progressive tumor lesion contained higher CD8+ T cell counts/mm2 and interferon-gamma (IFNγ) signature level, but similar tumor PD-L1 expression. The tumor mutational burden levels were in 2 out 3 lesions higher compared to the corresponding regressive tumors lesion. In the acquired tumor lesions, high CD8+/mm2 and relatively high IFNγ signature levels were observed. In one patient in both the B2M and PTEN gene a stop gaining mutation and in another patient a pathogenic POLE mutation were found. CONCLUSION: Intrapatient comparison of progressive versus regressive lesions indicates no defect in tumor T cell infiltration, and in general no tumor immune exclusion were observed.


Assuntos
Melanoma , Humanos , Inibidores de Checkpoint Imunológico , Estudos Retrospectivos , Linfócitos T CD8-Positivos , Interferon gama
4.
Nat Med ; 27(2): 256-263, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33558721

RESUMO

Neoadjuvant ipilimumab plus nivolumab showed high pathologic response rates (pRRs) in patients with macroscopic stage III melanoma in the phase 1b OpACIN ( NCT02437279 ) and phase 2 OpACIN-neo ( NCT02977052 ) studies1,2. While the results are promising, data on the durability of these pathologic responses and baseline biomarkers for response and survival were lacking. After a median follow-up of 4 years, none of the patients with a pathologic response (n = 7/9 patients) in the OpACIN study had relapsed. In OpACIN-neo (n = 86), the 2-year estimated relapse-free survival was 84% for all patients, 97% for patients achieving a pathologic response and 36% for nonresponders (P < 0.001). High tumor mutational burden (TMB) and high interferon-gamma-related gene expression signature score (IFN-γ score) were associated with pathologic response and low risk of relapse; pRR was 100% in patients with high IFN-γ score/high TMB; patients with high IFN-γ score/low TMB or low IFN-γ score/high TMB had pRRs of 91% and 88%; while patients with low IFN-γ score/low TMB had a pRR of only 39%. These data demonstrate long-term benefit in patients with a pathologic response and show the predictive potential of TMB and IFN-γ score. Our findings provide a strong rationale for a randomized phase 3 study comparing neoadjuvant ipilimumab plus nivolumab versus standard adjuvant therapy with antibodies against the programmed cell death protein-1 (anti-PD-1) in macroscopic stage III melanoma.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Ipilimumab/administração & dosagem , Melanoma/tratamento farmacológico , Nivolumabe/administração & dosagem , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Antígeno B7-H1/antagonistas & inibidores , Antígeno B7-H1/genética , Antígeno B7-H1/imunologia , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/imunologia , Antígeno CTLA-4/antagonistas & inibidores , Antígeno CTLA-4/genética , Antígeno CTLA-4/imunologia , Intervalo Livre de Doença , Feminino , Humanos , Imunoterapia/efeitos adversos , Interferon gama/genética , Ipilimumab/efeitos adversos , Masculino , Melanoma/imunologia , Melanoma/patologia , Pessoa de Meia-Idade , Mutação/genética , Terapia Neoadjuvante/efeitos adversos , Estadiamento de Neoplasias , Nivolumabe/efeitos adversos , Recidiva
5.
Ann Oncol ; 27(7): 1311-6, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27091807

RESUMO

BACKGROUND: Fibroblast growth factor receptor 3 (FGFR3) is an actionable target in bladder cancer. Preclinical studies show that anti-FGFR3 treatment slows down tumor growth, suggesting that this tyrosine kinase receptor is a candidate for personalized bladder cancer treatment, particularly in patients with mutated FGFR3. We addressed tumor heterogeneity in a large multicenter, multi-laboratory study, as this may have significant impact on therapeutic response. PATIENTS AND METHODS: We evaluated possible FGFR3 heterogeneity by the PCR-SNaPshot method in the superficial and deep compartments of tumors obtained by transurethral resection (TUR, n = 61) and in radical cystectomy (RC, n = 614) specimens and corresponding cancer-positive lymph nodes (LN+, n = 201). RESULTS: We found FGFR3 mutations in 13/34 (38%) T1 and 8/27 (30%) ≥T2-TUR samples, with 100% concordance between superficial and deeper parts in T1-TUR samples. Of eight FGFR3 mutant ≥T2-TUR samples, only 4 (50%) displayed the mutation in the deeper part. We found 67/614 (11%) FGFR3 mutations in RC specimens. FGFR3 mutation was associated with pN0 (P < 0.001) at RC. In 10/201 (5%) LN+, an FGFR3 mutation was found, all concordant with the corresponding RC specimen. In the remaining 191 cases, RC and LN+ were both wild type. CONCLUSIONS: FGFR3 mutation status seems promising to guide decision-making on adjuvant anti-FGFR3 therapy as it appeared homogeneous in RC and LN+. Based on the results of TUR, the deep part of the tumor needs to be assessed if neoadjuvant anti-FGFR3 treatment is considered. We conclude that studies on the heterogeneity of actionable molecular targets should precede clinical trials with these drugs in the perioperative setting.


Assuntos
Biomarcadores Tumorais/genética , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/genética , Neoplasias da Bexiga Urinária/tratamento farmacológico , Neoplasias da Bexiga Urinária/genética , Adulto , Idoso , Tomada de Decisão Clínica , Cistectomia , Feminino , Regulação Neoplásica da Expressão Gênica , Heterogeneidade Genética , Humanos , Linfonodos/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Período Perioperatório , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/cirurgia
7.
Br J Cancer ; 105(12): 1934-9, 2011 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-22033276

RESUMO

BACKGROUND: Somatic mutations in phosphoinositide-3-kinase catalytic subunit alpha (PIK3CA) are frequent in breast tumours and have been associated with oestrogen receptor (ER) expression, human epidermal growth factor receptor-2 overexpression, lymph node metastasis and poor survival. The goal of this study was to evaluate the association between inherited variation in this oncogene and risk of breast cancer. METHODS: A single-nucleotide polymorphism from the PIK3CA locus that was associated with breast cancer in a study of Caucasian breast cancer cases and controls from the Mayo Clinic (MCBCS) was genotyped in 5436 cases and 5280 controls from the Cancer Genetic Markers of Susceptibility (CGEMS) study and in 30 949 cases and 29 788 controls from the Breast Cancer Association Consortium (BCAC). RESULTS: Rs1607237 was significantly associated with a decreased risk of breast cancer in MCBCS, CGEMS and all studies of white Europeans combined (odds ratio (OR)=0.97, 95% confidence interval (CI) 0.95-0.99, P=4.6 × 10(-3)), but did not reach significance in the BCAC replication study alone (OR=0.98, 95% CI 0.96-1.01, P=0.139). CONCLUSION: Common germline variation in PIK3CA does not have a strong influence on the risk of breast cancer.


Assuntos
Neoplasias da Mama/enzimologia , Predisposição Genética para Doença , Variação Genética , Fosfatidilinositol 3-Quinases/genética , Neoplasias da Mama/genética , Estudos de Casos e Controles , Classe I de Fosfatidilinositol 3-Quinases , Feminino , Humanos
8.
Neurology ; 73(6): 430-7, 2009 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-19535770

RESUMO

OBJECTIVE: To describe the phenotype of adult patients with variant and classic ataxia-telangiectasia (A-T), to raise the degree of clinical suspicion for the diagnosis variant A-T, and to assess a genotype-phenotype relationship for mutations in the ATM gene. METHODS: Retrospective analysis of the clinical characteristics and course of disease in 13 adult patients with variant A-T of 9 families and 6 unrelated adults with classic A-T and mutation analysis of the ATM gene and measurements of ATM protein expression and kinase activity. RESULTS: Patients with variant A-T were only correctly diagnosed in adulthood. They often presented with extrapyramidal symptoms in childhood, whereas cerebellar ataxia appeared later. Four patients with variant A-T developed a malignancy. Patients with classic and variant A-T had elevated serum alpha-fetoprotein levels and chromosome 7/14 rearrangements. The mildest variant A-T phenotype was associated with missense mutations in the ATM gene that resulted in expression of some residual ATM protein with kinase activity. Two splicing mutations, c.331 + 5G>A and c.496 + 5G>A, caused a more severe variant A-T phenotype. The splicing mutation c.331 + 5G>A resulted in less ATM protein and kinase activity than the missense mutations. CONCLUSIONS: Ataxia-telangiectasia (A-T) should be considered in patients with unexplained extrapyramidal symptoms. Early diagnosis is important given the increased risk of malignancies and the higher risk for side effects of subsequent cancer treatment. Measurement of serum alpha-fetoprotein and chromosomal instability precipitates the correct diagnosis. There is a clear genotype-phenotype relation for A-T, since the severity of the phenotype depends on the amount of residual kinase activity as determined by the genotype.


Assuntos
Ataxia Telangiectasia/diagnóstico , Ataxia Telangiectasia/genética , Adulto , Fatores Etários , Feminino , Variação Genética/genética , Humanos , Masculino , Pessoa de Meia-Idade , Mutação/genética , Estudos Retrospectivos , Adulto Jovem
9.
Neurology ; 67(2): 346-9, 2006 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-16864838

RESUMO

The authors report four adult-onset ataxia telangiectasia (AT) patients belonging to two families lacking pronounced cerebellar ataxia but displaying distal spinal muscular atrophy. AT was proven by genetic studies showing ATM mutations and a reduced level of ATM. ATM activity, as measured by phosphorylation of p53, was close to normal, indicating that the p53 response is not the only factor in preventing neural damage in anterior horn cells in AT.


Assuntos
Ataxia Telangiectasia/diagnóstico , Ataxia Telangiectasia/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ligação a DNA/genética , Atrofia Muscular Espinal/diagnóstico , Atrofia Muscular Espinal/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Supressoras de Tumor/genética , Adulto , Ataxia Telangiectasia/complicações , Proteínas Mutadas de Ataxia Telangiectasia , Feminino , Predisposição Genética para Doença/genética , Humanos , Masculino , Atrofia Muscular Espinal/complicações
10.
Ned Tijdschr Geneeskd ; 147(9): 386-9, 2003 Mar 01.
Artigo em Holandês | MEDLINE | ID: mdl-12661456

RESUMO

Ataxia telangiectasia (AT) is an autosomal recessive disorder characterised by cerebellar ataxia, telangiectasia, immune defects, and a predisposition to malignancy. Chromosomal breakage is a feature. AT cells are abnormally sensitive to cell kill by ionising radiation and abnormally resistant to inhibition of DNA synthesis by ionising radiation. The responsible gene, 'ataxia telangiectasia mutated' (ATM) plays a crucial role in a signal transduction pathway, regulating the cell cycle, and in preventing damaged DNA from being reproduced. This rare genetic disorder manifests itself during childhood. The illness is progressive and most individuals die in their second or third decade of life due to infections or cancer. AT is difficult to diagnose due to its rarity and clinical heterogeneity. Both a physical examination and several laboratory tests are necessary for establishing its proper diagnosis.


Assuntos
Ataxia Telangiectasia/genética , Mutação , Proteínas Serina-Treonina Quinases/genética , Formação de Anticorpos/genética , Ataxia Telangiectasia/diagnóstico , Ataxia Telangiectasia/imunologia , Proteínas Mutadas de Ataxia Telangiectasia , Ciclo Celular/genética , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Diagnóstico Diferencial , Humanos , Imunidade Celular/genética , Exame Físico , Tolerância a Radiação/genética , Tolerância a Radiação/fisiologia , Transdução de Sinais , Proteínas Supressoras de Tumor
11.
Int J Radiat Biol ; 76(5): 693-8, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10866292

RESUMO

PURPOSE: Long-term survivors of Hodgkin's disease who received mantle-field irradiation at a young age have a strongly increased risk of developing breast cancer. The purpose of this study was to investigate whether this increased risk was substantially greater among women heterozygous for a germline mutation in the ataxia-telangiectasia gene (ATM). MATERIALS AND METHODS: Thirty-two patients were selected who had developed breast cancer at least 10 years following irradiation for Hodgkin's disease before the age of 45 years. In these patients, the complete open reading frame of the ATM gene was analysed for the presence of germline mutations using the protein truncation test and two mutation-specific tests, followed by genomic sequencing. RESULTS: No A-T disease causing germline mutations were found in these selected Hodgkin patients. However, several alternative splicing events were detected which might influence protein expression levels. CONCLUSIONS: The data suggest that truncating mutations in the ATM gene are not a major component underlying the increased risk of breast cancer following Hodgkin's disease.


Assuntos
Neoplasias da Mama/etiologia , Neoplasias da Mama/genética , Mutação em Linhagem Germinativa , Doença de Hodgkin/radioterapia , Neoplasias Induzidas por Radiação/genética , Proteínas Serina-Treonina Quinases/genética , Radioterapia/efeitos adversos , Adulto , Proteínas Mutadas de Ataxia Telangiectasia , Proteínas de Ciclo Celular , Análise Mutacional de DNA , Enzimas de Restrição do DNA/metabolismo , DNA Complementar/metabolismo , Proteínas de Ligação a DNA , Feminino , Deleção de Genes , Humanos , Leucócitos Mononucleares/metabolismo , Fases de Leitura Aberta , Risco , Proteínas Supressoras de Tumor
12.
Am J Hum Genet ; 66(2): 494-500, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10677309

RESUMO

Approximately 0.5%-1% of the general population has been estimated to be heterozygous for a germline mutation in the ATM gene. Mutations in the ATM gene are responsible for the autosomal recessive disorder ataxia-telangiectasia (A-T) (MIM 208900). The finding that ATM-heterozygotes have an increased relative risk for breast cancer was supported by some studies but not confirmed by others. In view of this discrepancy, we examined the frequency of ATM germline mutations in a selected group of Dutch patients with breast cancer. We have analyzed ATM germline mutations in normal blood lymphocytes, using the protein-truncation test followed by genomic-sequence analysis. A high percentage of ATM germline mutations was demonstrated among patients with sporadic breast cancer. The 82 patients included in this study had developed breast cancer at age <45 and had survived >/=5 years (mean 15 years), and in 33 (40%) of the patients a contralateral breast tumor had been diagnosed. Among these patients we identified seven (8.5%) ATM germline mutations, of which five are distinct. One splice-site mutation (IVS10-6T-->G) was detected three times in our series. Four heterozygous carriers were patients with bilateral breast cancer. Our results indicate that the mutations identified in this study are "A-T disease-causing" mutations that might be associated with an increased risk of breast cancer in heterozygotes. We conclude that ATM heterozygotes have an approximately ninefold-increased risk of developing a type of breast cancer characterized by frequent bilateral occurrence, early age at onset, and long-term survival. The specific characteristics of our population of patients may explain why such a high frequency was not found in other series.


Assuntos
Neoplasias da Mama/genética , Predisposição Genética para Doença/genética , Mutação em Linhagem Germinativa/genética , Proteínas Serina-Treonina Quinases/genética , Adulto , Idade de Início , Alelos , Processamento Alternativo , Proteínas Mutadas de Ataxia Telangiectasia , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/epidemiologia , Carcinoma Ductal de Mama/genética , Carcinoma Ductal de Mama/mortalidade , Carcinoma Ductal de Mama/patologia , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Éxons/genética , Feminino , Frequência do Gene/genética , Haplótipos , Heterozigoto , Humanos , Perda de Heterozigosidade/genética , Masculino , Repetições de Microssatélites/genética , Pessoa de Meia-Idade , Países Baixos/epidemiologia , Sequências Reguladoras de Ácido Nucleico/genética , Proteínas Supressoras de Tumor
13.
Genes Chromosomes Cancer ; 25(3): 212-21, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10379867

RESUMO

Among the chromosomal regions commonly undergoing deletions in breast tumors is 11q23.1. The genes that are targets for loss of heterozygosity (LOH) in this region is not yet established. One of the candidate genes located in this region is ATM, responsible for the rare autosomal recessive disorder ataxia-telangiectasia (A-T). Interestingly, A-T heterozygotes may have an increased risk of cancer, in particular breast cancer, although this is still controversial. A common assumption has been that the target for the LOH at 11q23.1 in breast carcinoma is the ATM gene, but the area studied has been too large, the density of markers too low, and the number of tumors studied has been too small to draw any firm conclusions. The present study is a multicenter study including 918 breast cancer patients with clinical information and survival data available for most of them. Primary breast tumors were investigated for LOH using a high density of microsatellite markers spanning approximately 6 Mb around the ATM gene. Survival analyses showed that there are most likely one or more candidate genes in a 3-4 Mb region between the markers D11S1819 and D11S927 including the ATM gene. Cancer-specific survival was significantly reduced in patients whose tumors exhibited LOH of markers D11S2179 (within the ATM gene), D11S1778, D11S1294, and D11S1818. The highest survival hazard ratios were 1.8(C11.2-2.8, P = 0.010) and 2.1 (C11.4-3.0, P = 0.0004) for markers D11S2179 and D11S1818, respectively. One or more of these markers are therefore most likely to be located close to or within genes associated with breast cancer survival.


Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/mortalidade , Cromossomos Humanos Par 11/genética , Perda de Heterozigosidade/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/genética , Carcinoma Ductal de Mama/mortalidade , Carcinoma Ductal de Mama/patologia , Mapeamento Cromossômico , Feminino , Marcadores Genéticos , Humanos , Pessoa de Meia-Idade , Taxa de Sobrevida , Translocação Genética
14.
Hum Mutat ; 12(5): 330-7, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9792409

RESUMO

Germline mutations in the ATM gene are responsible for the autosomal recessive disorder ataxia-telangiectasia (A-T). In our study, we have determined the ATM mutation spectrum in 19 classical A-T patients, including some immigrant populations, as well as 12 of Dutch ethnic origin. Both the protein truncation test (PTT) and the restriction endonuclease fingerprinting (REF) method were used and compared for their detection efficiency, identifying 76% and 60% of the mutations, respectively. Most patients were found to be compound heterozygote. Seventeen mutations were distinct, of which 10 were not reported previously. Mutations are small deletions or point mutations frequently affecting splice sites. Moreover, a 16.7-kb genomic deletion of the 3' end of the gene, most likely a result of recombination between two LINE elements, was identified. The most frequently found mutation, identified in three unrelated Turkish A-T individuals, was previously described to be a Turkish A-T founder mutation. The presence of a founder mutation among relatively small ethnic population groups in Western Europe could indicate a high carrier frequency in such communities. In patients of Dutch ethnic origin, however, no significant founder effect could be identified. The observed genetic heterogeneity including the relative high percentage of splice-site mutations had no reflection on the phenotype. All patients manifested classical A-T and increased cellular radioresistant DNA synthesis.


Assuntos
Ataxia Telangiectasia/genética , Mutação em Linhagem Germinativa , Proteínas Serina-Treonina Quinases , Proteínas/genética , Ataxia Telangiectasia/etnologia , Proteínas Mutadas de Ataxia Telangiectasia , Proteínas de Ciclo Celular , Células Cultivadas , Análise Mutacional de DNA , Proteínas de Ligação a DNA , Efeito Fundador , Humanos , Países Baixos , Proteínas Supressoras de Tumor
15.
EMBO J ; 14(9): 1858-66, 1995 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-7743993

RESUMO

P-glycoproteins can cause resistance of mammalian tumor cells to chemotherapeutic drugs. They belong to an evolutionarily well-conserved family of ATP binding membrane transporters. Four P-glycoprotein gene homologs have been found in the nematode Caenorhabditis elegans; this report describes the functional analysis of two. We found that PGP-3 is expressed in both the apical membrane of the excretory cell and in the apical membrane of intestinal cells, whereas PGP-1 is expressed only in the apical membrane of the intestinal cells and the intestinal valve. By transposon-mediated deletion mutagenesis we generated nematode strains with deleted P-glycoprotein genes and found that the pgp-3 deletion mutant, but not the pgp-1 mutant, is sensitive to both colchicine and chloroquine. Our results suggest that soil nematodes have P-glycoproteins to protect themselves against toxic compounds made by plants and microbes in the rhizosphere.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/metabolismo , Proteínas de Helminto/metabolismo , Toxinas Biológicas/toxicidade , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Animais , Animais Geneticamente Modificados , Sequência de Bases , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Cloroquina/farmacologia , Colchicina/farmacologia , DNA de Helmintos/genética , Resistência a Medicamentos/genética , Genes de Helmintos , Proteínas de Helminto/genética , Microscopia Eletrônica , Dados de Sequência Molecular , Mutação , Distribuição Tecidual
16.
EMBO J ; 12(4): 1615-20, 1993 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8096815

RESUMO

P-glycoproteins can cause multidrug resistance in mammalian tumor cells by active extrusion of cytotoxic drugs. The natural function of these evolutionarily conserved, membrane-bound ATP binding transport proteins is unknown. In mammals, P-glycoproteins are abundantly present in organs associated with the digestive tract. We have studied the tissue-specific expression of Caenorhabditis elegans P-glycoprotein genes pgp-1 and pgp-3 by transformation of nematodes with pgp-lacZ gene fusion constructs in which the promoter area of the pgp genes was fused to the coding region of lacZ. Expression of pgp-1 and pgp-3, as inferred from pgp-lacZ transgenic nematodes, was confined to the intestinal cells. The expression patterns of both genes were virtually indistinguishable. Quantitative analysis of pgp mRNA levels during development showed that pgp-1, -2, and -3 were expressed throughout the life cycle of C.elegans, albeit with some variation indicating developmental regulation. The expression of P-glycoprotein genes in intestinal cells is an evolutionarily conserved feature of these genes, consistent with the hypothesis that P-glycoproteins provide a mechanism of protection against environmental toxins.


Assuntos
Caenorhabditis/genética , Glicoproteínas de Membrana/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP , Animais , Animais Geneticamente Modificados , Caenorhabditis/crescimento & desenvolvimento , Resistência a Medicamentos , Expressão Gênica , Genes , Mucosa Intestinal/metabolismo , Regiões Promotoras Genéticas , RNA Mensageiro/genética , Proteínas Recombinantes de Fusão/genética
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