RESUMO
High grade serous ovarian carcinoma (HGSOC) is a highly heterogeneous disease that typically presents at an advanced, metastatic state. The multi-scale complexity of HGSOC is a major obstacle to predicting response to neoadjuvant chemotherapy (NACT) and understanding critical determinants of response. Here we present a framework to predict the response of HGSOC patients to NACT integrating baseline clinical, blood-based, and radiomic biomarkers extracted from all primary and metastatic lesions. We use an ensemble machine learning model trained to predict the change in total disease volume using data obtained at diagnosis (n = 72). The model is validated in an internal hold-out cohort (n = 20) and an independent external patient cohort (n = 42). In the external cohort the integrated radiomics model reduces the prediction error by 8% with respect to the clinical model, achieving an AUC of 0.78 for RECIST 1.1 classification compared to 0.47 for the clinical model. Our results emphasize the value of including radiomics data in integrative models of treatment response and provide methods for developing new biomarker-based clinical trials of NACT in HGSOC.
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Neoplasias Ovarianas , Humanos , Feminino , Neoplasias Ovarianas/diagnóstico por imagem , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Terapia Neoadjuvante/métodos , Biomarcadores Tumorais/genéticaRESUMO
The drivers of recurrence and resistance in ovarian high grade serous carcinoma remain unclear. We investigate the acquisition of resistance by collecting tumour biopsies from a cohort of 276 women with relapsed ovarian high grade serous carcinoma in the BriTROC-1 study. Panel sequencing shows close concordance between diagnosis and relapse, with only four discordant cases. There is also very strong concordance in copy number between diagnosis and relapse, with no significant difference in purity, ploidy or focal somatic copy number alterations, even when stratified by platinum sensitivity or prior chemotherapy lines. Copy number signatures are strongly correlated with immune cell infiltration, whilst diagnosis samples from patients with primary platinum resistance have increased rates of CCNE1 and KRAS amplification and copy number signature 1 exposure. Our data show that the ovarian high grade serous carcinoma genome is remarkably stable between diagnosis and relapse and acquired chemotherapy resistance does not select for common copy number drivers.
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Cistadenocarcinoma Seroso , Neoplasias Ovarianas , Humanos , Feminino , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Variações do Número de Cópias de DNA/genética , Recidiva Local de Neoplasia/genética , Mutação , Cistadenocarcinoma Seroso/tratamento farmacológico , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/patologiaRESUMO
PURPOSE: Chromosomal aberration and DNA copy number change are robust hallmarks of cancer. The gold standard for detecting copy number changes in tumor cells is fluorescence in situ hybridization (FISH) using locus-specific probes that are imaged as fluorescent spots. However, spot counting often does not perform well on solid tumor tissue sections due to partially represented or overlapping nuclei. MATERIALS AND METHODS: To overcome these challenges, we have developed a computational approach called FrenchFISH, which comprises a nuclear volume correction method coupled with two types of Poisson models: either a Poisson model for improved manual spot counting without the need for control probes or a homogeneous Poisson point process model for automated spot counting. RESULTS: We benchmarked the performance of FrenchFISH against previous approaches using a controlled simulation scenario and tested it experimentally in 12 ovarian carcinoma FFPE-tissue sections for copy number alterations at three loci (c-Myc, hTERC, and SE7). FrenchFISH outperformed standard spot counting with 74% of the automated counts having < 1 copy number difference from the manual counts and 17% having < 2 copy number differences, while taking less than one third of the time of manual counting. CONCLUSION: FrenchFISH is a general approach that can be used to enhance clinical diagnosis on sections of any tissue by both speeding up and improving the accuracy of spot count estimates.
Assuntos
Aberrações Cromossômicas , Variações do Número de Cópias de DNA , Simulação por Computador , DNA , Variações do Número de Cópias de DNA/genética , Humanos , Hibridização in Situ FluorescenteRESUMO
PURPOSE: The known epithelial ovarian cancer (EOC) susceptibility genes account for less than 50% of the heritable risk of ovarian cancer suggesting that other susceptibility genes exist. The aim of this study was to evaluate the contribution to ovarian cancer susceptibility of rare deleterious germline variants in a set of candidate genes. METHODS: We sequenced the coding region of 54 candidate genes in 6385 invasive EOC cases and 6115 controls of broad European ancestry. Genes with an increased frequency of putative deleterious variants in cases versus controls were further examined in an independent set of 14 135 EOC cases and 28 655 controls from the Ovarian Cancer Association Consortium and the UK Biobank. For each gene, we estimated the EOC risks and evaluated associations between germline variant status and clinical characteristics. RESULTS: The ORs associated for high-grade serous ovarian cancer were 3.01 for PALB2 (95% CI 1.59 to 5.68; p=0.00068), 1.99 for POLK (95% CI 1.15 to 3.43; p=0.014) and 4.07 for SLX4 (95% CI 1.34 to 12.4; p=0.013). Deleterious mutations in FBXO10 were associated with a reduced risk of disease (OR 0.27, 95% CI 0.07 to 1.00, p=0.049). However, based on the Bayes false discovery probability, only the association for PALB2 in high-grade serous ovarian cancer is likely to represent a true positive. CONCLUSIONS: We have found strong evidence that carriers of PALB2 deleterious mutations are at increased risk of high-grade serous ovarian cancer. Whether the magnitude of risk is sufficiently high to warrant the inclusion of PALB2 in cancer gene panels for ovarian cancer risk testing is unclear; much larger sample sizes will be needed to provide sufficiently precise estimates for clinical counselling.
Assuntos
Proteína do Grupo de Complementação N da Anemia de Fanconi/genética , Predisposição Genética para Doença , Neoplasias Ovarianas/genética , Estudos de Casos e Controles , Feminino , Variação Genética , Humanos , Medição de RiscoRESUMO
PURPOSE: Gene expression-based molecular subtypes of high-grade serous tubo-ovarian cancer (HGSOC), demonstrated across multiple studies, may provide improved stratification for molecularly targeted trials. However, evaluation of clinical utility has been hindered by nonstandardized methods, which are not applicable in a clinical setting. We sought to generate a clinical grade minimal gene set assay for classification of individual tumor specimens into HGSOC subtypes and confirm previously reported subtype-associated features. EXPERIMENTAL DESIGN: Adopting two independent approaches, we derived and internally validated algorithms for subtype prediction using published gene expression data from 1,650 tumors. We applied resulting models to NanoString data on 3,829 HGSOCs from the Ovarian Tumor Tissue Analysis consortium. We further developed, confirmed, and validated a reduced, minimal gene set predictor, with methods suitable for a single-patient setting. RESULTS: Gene expression data were used to derive the predictor of high-grade serous ovarian carcinoma molecular subtype (PrOTYPE) assay. We established a de facto standard as a consensus of two parallel approaches. PrOTYPE subtypes are significantly associated with age, stage, residual disease, tumor-infiltrating lymphocytes, and outcome. The locked-down clinical grade PrOTYPE test includes a model with 55 genes that predicted gene expression subtype with >95% accuracy that was maintained in all analytic and biological validations. CONCLUSIONS: We validated the PrOTYPE assay following the Institute of Medicine guidelines for the development of omics-based tests. This fully defined and locked-down clinical grade assay will enable trial design with molecular subtype stratification and allow for objective assessment of the predictive value of HGSOC molecular subtypes in precision medicine applications.See related commentary by McMullen et al., p. 5271.
Assuntos
Cistadenoma Seroso/genética , Proteínas de Neoplasias/genética , Neoplasias Ovarianas/genética , Transcriptoma/genética , Idoso , Algoritmos , Cistadenoma Seroso/classificação , Cistadenoma Seroso/patologia , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Linfócitos do Interstício Tumoral/patologia , Pessoa de Meia-Idade , Gradação de Tumores , Neoplasia Residual/classificação , Neoplasia Residual/genética , Neoplasia Residual/patologia , Neoplasias Ovarianas/classificação , Neoplasias Ovarianas/patologiaRESUMO
PURPOSE: Germline BRCA1 and/or BRCA2 mutations (gBRCAms) are risk factors for pancreatic cancer. The extent to which demographic and geographic factors affect the uptake of gBRCAm testing in pancreatic cancer (PC) is unknown. METHODS: We conducted a retrospective, descriptive analysis of demographic/geographic data from the first 2,206 patients with metastatic PC (mPC) screened for eligibility to enter the phase III POLO trial of maintenance olaparib. No formal statistical tests were performed. RESULTS: Of 2,167 patients with previously unknown gBRCAm status, 128 (5.9%) had a newly identified gBRCAm; rates were highest in the United States, France, and Israel (9.5%, 7.6%, and 7.4%, respectively). When including patients with a previously known gBRCAm, prevalence rose to 7.2% (or 5.8% after excluding populations enriched in Ashkenazi Jews, who are known to have a high rate of BRCA1 and BRCA2 founder mutations). Patients with a gBRCAm were slightly younger (57.9 v 61.1 years) and more likely to have early-onset mPC than those without. Higher newly identified gBRCAm prevalence was observed among African American (n = 28) versus white (n = 1,808), Asian (n = 218), and other (n = 61) patients (10.7% v 6.1%, 5.0%, and 1.6%, respectively). Of 139 white patients with a gBRCAm, 110 were newly identified during screening; the majority of gBRCAms in African American, Asian, and Hispanic patients (n = 3, n = 11, and n = 5, respectively) were newly identified. CONCLUSION: We identified substantial geographic and some racial variability in gBRCAm prevalence among patients with mPC, an important consideration given the increased use of familial screening and possible future use of targeted therapies in this setting. Although our study included small numbers of nonwhite patients, prior knowledge of their gBRCAm status was limited compared with their white counterparts, which suggests disparities in genetic testing uptake.
Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Testes Genéticos/métodos , Mutação em Linhagem Germinativa , Judeus/genética , Neoplasias Pancreáticas/genética , Adulto , Idoso , Austrália/epidemiologia , Canadá/epidemiologia , Feminino , Humanos , Israel/epidemiologia , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/epidemiologia , Prevalência , Estudos Retrospectivos , Estados Unidos/epidemiologiaRESUMO
Existing methods to improve detection of circulating tumor DNA (ctDNA) have focused on genomic alterations but have rarely considered the biological properties of plasma cell-free DNA (cfDNA). We hypothesized that differences in fragment lengths of circulating DNA could be exploited to enhance sensitivity for detecting the presence of ctDNA and for noninvasive genomic analysis of cancer. We surveyed ctDNA fragment sizes in 344 plasma samples from 200 patients with cancer using low-pass whole-genome sequencing (0.4×). To establish the size distribution of mutant ctDNA, tumor-guided personalized deep sequencing was performed in 19 patients. We detected enrichment of ctDNA in fragment sizes between 90 and 150 bp and developed methods for in vitro and in silico size selection of these fragments. Selecting fragments between 90 and 150 bp improved detection of tumor DNA, with more than twofold median enrichment in >95% of cases and more than fourfold enrichment in >10% of cases. Analysis of size-selected cfDNA identified clinically actionable mutations and copy number alterations that were otherwise not detected. Identification of plasma samples from patients with advanced cancer was improved by predictive models integrating fragment length and copy number analysis of cfDNA, with area under the curve (AUC) >0.99 compared to AUC <0.80 without fragmentation features. Increased identification of cfDNA from patients with glioma, renal, and pancreatic cancer was achieved with AUC > 0.91 compared to AUC < 0.5 without fragmentation features. Fragment size analysis and selective sequencing of specific fragment sizes can boost ctDNA detection and could complement or provide an alternative to deeper sequencing of cfDNA.
Assuntos
DNA Tumoral Circulante/análise , DNA Tumoral Circulante/química , Animais , DNA Tumoral Circulante/sangue , Variações do Número de Cópias de DNA/genética , Genoma Humano , Humanos , Aprendizado de Máquina , Camundongos , Mutação/genética , Sequenciamento Completo do GenomaRESUMO
The genomic complexity of profound copy number aberrations has prevented effective molecular stratification of ovarian cancers. Here, to decode this complexity, we derived copy number signatures from shallow whole-genome sequencing of 117 high-grade serous ovarian cancer (HGSOC) cases, which were validated on 527 independent cases. We show that HGSOC comprises a continuum of genomes shaped by multiple mutational processes that result in known patterns of genomic aberration. Copy number signature exposures at diagnosis predict both overall survival and the probability of platinum-resistant relapse. Measurement of signature exposures provides a rational framework to choose combination treatments that target multiple mutational processes.
Assuntos
Variações do Número de Cópias de DNA , Mutação , Neoplasias Ovarianas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Genômica/métodos , Humanos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/genética , Sequenciamento Completo do Genoma/métodosRESUMO
We analyzed whole exome sequencing data in germline DNA from 412 high grade serous ovarian cancer (HGSOC) cases from The Cancer Genome Atlas Project and identified 5,517 genes harboring a predicted deleterious germline coding mutation in at least one HGSOC case. Gene-set enrichment analysis showed enrichment for genes involved in DNA repair (p = 1.8×10-3). Twelve DNA repair genes - APEX1, APLF, ATX, EME1, FANCL, FANCM, MAD2L2, PARP2, PARP3, POLN, RAD54L and SMUG1 - were prioritized for targeted sequencing in up to 3,107 HGSOC cases, 1,491 cases of other epithelial ovarian cancer (EOC) subtypes and 3,368 unaffected controls of European origin. We estimated mutation prevalence for each gene and tested for associations with disease risk. Mutations were identified in both cases and controls in all genes except MAD2L2, where we found no evidence of mutations in controls. In FANCM we observed a higher mutation frequency in HGSOC cases compared to controls (29/3,107 cases, 0.96 percent; 13/3,368 controls, 0.38 percent; P=0.008) with little evidence for association with other subtypes (6/1,491, 0.40 percent; P=0.82). The relative risk of HGSOC associated with deleterious FANCM mutations was estimated to be 2.5 (95% CI 1.3 - 5.0; P=0.006). In summary, whole exome sequencing of EOC cases with large-scale replication in case-control studies has identified FANCM as a likely novel susceptibility gene for HGSOC, with mutations associated with a moderate increase in risk. These data may have clinical implications for risk prediction and prevention approaches for high-grade serous ovarian cancer in the future and a significant impact on reducing disease mortality.
RESUMO
BACKGROUND: The anticoagulant therapy with acenocoumarol is generally associated with a high risk of bleeding and thromboembolic events. PURPOSE: We applied eight already existing acenocoumarol dosing algorithms to Bulgarian patients with low acenocoumarol dose requirements and investigated which of these algorithms would predict most precisely the dose anticoagulant. MATERIALS AND METHODS: Two patients with Bulgarian origin were referred to the outpatient clinical laboratory of "St. Ekaterina" University Hospital for Cardiovascular Surgery and Cardiology, Sofia, Bulgaria. After obtaining written informed consent, both patients were genotyped for polymorphisms in genes for Cytochrome P450 2C9 (CYP2C9), Vitamin K epoxide reductase (VKORC1), Apolipoprotein E (APOE), and Cytochrome P450 4F2 (CYP4F2). RESULTS: All applied acenocoumarol dosing algorithms predicted relatively similar doses of coumarin anticoagulant in both patients. However, van Schie et al.'s algorithm allowed more accurate calculation of the optimal dose in our patients with extremely low acenocoumarol requirements. Genotyping of selected polymorphic variants in CYP2C9 and VKORC1 showed that both patients were compound heterozygotes for CYP2C9 (CYP2C9*2/*3) and homozygotes for both variants in VKORC1 (VKORC1 1173 T/T, and VKORC1-1639 A/A). This combination of genotypes suggested high sensitivity to acenocoumarol leading to the low anticoagulant dose requirements (0.25 and 1 mg/day, respectively) needed to reach the target International Normalized Ratio of 2.5-3.5. CONCLUSIONS: The genotyping of polymorphic variants in VKORC1 and CYP2C9, together with clinical and demographic parameters, can serve for more precise definition of the individual starting and maintenance doses of coumarin derivatives in each patient.
Assuntos
Acenocumarol/uso terapêutico , Anticoagulantes/uso terapêutico , Valva Aórtica/cirurgia , Valva Mitral/cirurgia , Tromboembolia/tratamento farmacológico , Algoritmos , Bulgária , Cumarínicos/uso terapêutico , Relação Dose-Resposta a Droga , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Farmacogenética/métodos , Polimorfismo de Nucleotídeo ÚnicoRESUMO
The aim of the present study was to determine the relative quantitative expression of hypoxia-inducible factor (HIF)-1α, -2α and -3α, and VEGF-A in laryngeal carcinoma. A total of 63 patients with carcinoma of the larynx were enrolled in the study. Total RNA was isolated from fresh, frozen normal and tumor tissues of each patient, and quantitative polymerase chain reaction was performed. HIF-1α was upregulated in the majority of patients (44 patients; 69.84%). By contrast, only 7 (11.11%) patients from the whole group displayed HIF-2α overexpression, while the HIF-3α isoform was silenced in the majority of patients (48 patients, 76.19%). A small group of 5 (7.94%) patients exhibited significant overexpression of the HIF-3α isoform. VEGF-A expression was significantly higher (P<0.05) in patients with upregulated HIF-1α (2.72±1.41 RQ) compared with patients without upregulated HIF-1α (1.86±1.46 RQ). There was a moderate positive correlation between mRNA expression levels of HIF-1α and VEGF-A (rs=0.392; P<0.005). To the best of our knowledge, this study is first to report quantitative data with regard to the expression of all three HIF isoforms in malignant neoplasms. The findings suggest the existence of specific phenotypes of HIF expression in laryngeal carcinoma, where the HIF switch is absent.
RESUMO
BACKGROUND AND OBJECTIVE: Pathogenic mutations in BRCA1/2 tumor suppressor genes increase the lifetime risk for developing breast and ovarian cancer. The aim of the present study was to evaluate the sensitivity and specificity of the Ion Torrent PGM™ for diagnostic mutation screening of BRCA1/2 genes. METHODS: In the current study we included a cohort of 58 Bulgarian high-risk breast cancer patients to validate a next-generation sequencing approach for diagnostic mutation screening of the BRCA1/2 genes using the Ion Torrent Personal Genome Machine® (PGM™) platform. We have also optimized the workflow by comparing two different library preparation methods and using three software packages: NextGENE, Torrent Suite variantCaller, and Samtools/BCFtools to achieve detection of all variants with high specificity and sensitivity. RESULTS: We have validated a quick and accurate diagnostic test, with an overall specificity of 95.9% and sensitivity of up to 100%, which can be the first method of choice, followed by confirmation of the identified variants by Sanger sequencing. Our results prove that the Ion AmpliSeq™ BRCA1/2 Community Panel used with the PGM™ platform, and coupled with our variant selection pipeline, is able to detect all sequence variants discovered by Sanger sequencing. CONCLUSION: The application of the new test which outperforms the classical approach in turn-around time and price will have great impact in the clinical practice to identify the mutation carriers and guide the better personalized treatment of the patients, as well as to contribute for the improved prophylaxis in hereditary breast and ovarian cancer families.
Assuntos
Genes BRCA1 , Genes BRCA2 , Testes Genéticos , Sequenciamento de Nucleotídeos em Larga Escala , Mutação , Alelos , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Biologia Computacional , Éxons , Feminino , Biblioteca Gênica , Testes Genéticos/métodos , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Polimorfismo de Nucleotídeo Único , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fluxo de TrabalhoRESUMO
Laryngeal squamous cell carcinoma (LSCC) is the second most common tumour of the head and neck. It is characterized by frequent aberrations in two cell-cycle regulators--CDKN2A and TP53. However, LSCC has been often studied as a part of the group of head and neck cancers and not as an individual entity. In the current study we aimed to examine mutation status of CDKN2A and TP53 genes in 108 LSCC patients. DNA was extracted from fresh-frozen tumour tissues; exons 1-3 of CDKN2A and exons 5-8 of TP53 were screened for mutations by direct sequencing. Genetic aberrations in CDKN2A were found in 16 (14.2%) and those in TP53--in 56/108 (51.9%) tumours. Seven mutations (two insertions, three deletions, one missense and one silent) detected in CDKN2A were not described previously. Also, we found seven novel deletions and a novel indel in TP53. No significant associations with clinical features were found. However, TP53 mutations were predominantly observed in smokers with advanced stage tumours. Screening for genetic aberrations in a defined group of LSCC contributes to the knowledge about laryngeal carcinogenesis. Further investigations are required to confirm the observed trends in associations with clinical features.
Assuntos
Carcinoma de Células Escamosas/genética , Inibidor p16 de Quinase Dependente de Ciclina/genética , Neoplasias Laríngeas/genética , Mutação/genética , Proteína Supressora de Tumor p53/genética , Carcinoma de Células Escamosas/diagnóstico , DNA de Neoplasias/genética , Feminino , Genes Neoplásicos/genética , Neoplasias de Cabeça e Pescoço/genética , Humanos , Neoplasias Laríngeas/diagnóstico , Masculino , Pessoa de Meia-Idade , Prognóstico , Análise de Sequência de DNARESUMO
Mutations in genes encoding isocitrate dehydrogenase isoforms 1 (IDH1) and 2 (IDH2) have been associated with good prognosis for patients with brain neoplasias and have been commonly found together with mutated TP53 gene. To determine the prevalence of IDH1, IDH2, and TP53 mutations and their impact on overall survival 106 glioblastoma patients were analysed. IDH1 mutations were detected in 13 and IDH2 mutation in one patient. Two homozygous samples with R132H mutation in IDH1 gene and a novel aberration K129R in IDH2 gene were found. Sixty-four percent of IDH1/IDH2 mutated tumours harboured also a mutation in TP53 gene. Genetic aberrations in TP53 were present in 37 patients. Statistical analysis of the impact of the studied factors on the overall survival showed that the mutations in IDH1/IDH2, but not the ones in TP53, were associated with longer survival. Also, the impact of age on prognosis was confirmed. This is the first comprehensive study on glioblastomas in Bulgaria. Our results suggest that IDH1/IDH2 but not TP53 mutations together with other prognostic factors such as age might be applied in clinical practice for prediction of outcome in patients with glioblastomas.
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Neoplasias Encefálicas/genética , Genes p53 , Glioblastoma/genética , Isocitrato Desidrogenase/genética , Proteína Supressora de Tumor p53/genética , Neoplasias Encefálicas/diagnóstico , Bulgária , Aberrações Cromossômicas , Feminino , Glioblastoma/diagnóstico , Homozigoto , Humanos , Estimativa de Kaplan-Meier , Perda de Heterozigosidade , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Mutação , Reação em Cadeia da Polimerase , Prognóstico , Modelos de Riscos Proporcionais , Análise de Sequência de DNARESUMO
BACKGROUND: Laryngeal squamous cell carcinoma (laryngeal SCC) is a frequently occurring cancer of the head and neck area. Epigenetic changes of tumor-related genes contribute to its genesis and progression. METHODS: We assessed promoter methylation status of the selected genes (CDKN2A, MGMT, MLH1, and DAPK) using methylation-sensitive high resolution melting (MS-HRM) in 100 patients with laryngeal SCC and studied the correlations with clinical characteristics. RESULTS: The prevalence of promoter methylation in MGMT, CDKN2A, MLH1, and DAPK was 59 of 97 (60.8%), 46 of 97 (47.4%), 45 of 97 (46.4%), and 41 of 97 patients (42.3%), respectively. Significantly increased methylation of CDKN2A was observed in heavy smokers. Epigenetic inactivation of CDKN2A and MLH1 were found to be associated with lymph node involvement. An inverse correlation was present between MLH1 methylation and alcohol consumption. CONCLUSION: Our results strongly suggest that deregulation of p16-associated, and MLH1-associated pathways, because of promoter hypermethylation, is associated with increased cancer cell migration, tumor invasiveness, and, thus, aggressive phenotype.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Carcinoma de Células Escamosas/genética , Inibidor p16 de Quinase Dependente de Ciclina/genética , Metilação de DNA , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Proteínas Quinases Associadas com Morte Celular/genética , Neoplasias Laríngeas/genética , Proteínas Nucleares/genética , Proteínas Supressoras de Tumor/genética , Adulto , Idoso , Bulgária , Carcinoma de Células Escamosas/patologia , Feminino , Humanos , Neoplasias Laríngeas/patologia , Masculino , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL , Prevalência , Regiões Promotoras GenéticasRESUMO
Intratumor heterogeneity-heterogeneity of cancer cells within a single tumor-is considered one of the most problematic factors of treatment. Genetic heterogeneity, such as in somatic mutations and chromosome aberrations, is a common characteristic of human solid tumors and is probably the basis of biological heterogeneity. Using mutations in APC, TP53 and KRAS as markers to identify distinct colorectal cancer subpopulations, we analyzed a total of 42 primary colorectal cancer tissues and six paired liver metastases with multipoint microsampling, which enabled analysis of mutation patterns and allelic imbalances with a resolution of 0.01 mm(2) (about 200 cells). There was usually more than one subpopulation in each primary tumor. Only two of 15 (13.3%) cases with three gene mutations and eight of 27 (29.6%) cases with two gene mutations had a single subpopulation. Cells with mutations in all of the examined genes usually constituted the major population. Multipoint microsampling of six primary and metastatic tumor pairs revealed that the majority of discrepancies in mutation patterns found with the bulk tissue analysis were due to loss of subpopulations in the metastatic tissues. In addition, multipoint microsampling uncovered substantial changes in subpopulations that were not detected with bulk tissue analysis. Specifically, the proportion of KRAS mutation-negative subpopulations increased in the metastatic tumors of four cases. Because KRAS mutation status is linked to cetuximab/panitumumab efficacy, subpopulation dynamics could lead to differences in response to cetuximab/panitumumab in primary versus metastatic tumors.
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Neoplasias Colorretais/patologia , Metástase Neoplásica/patologia , Proteína da Polipose Adenomatosa do Colo/genética , Neoplasias Colorretais/genética , Genótipo , Humanos , Mutação , Metástase Neoplásica/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas p21(ras) , Proteína Supressora de Tumor p53/genética , Proteínas ras/genéticaRESUMO
OBJECTIVE: van't Veer and colleagues developed a 70-gene prognosis profile known as MammaPrint to identify breast cancer patients who were at low risk of developing metastases. We evaluated the prognostic value of the 70-gene MammaPrint profile in Japanese women with node-negative breast cancer. METHODS: Frozen tumour samples from 102 eligible node-negative breast cancer patients aged 70 or younger were characterized with the MammaPrint array. The patients were treated with breast-conserving therapy or mastectomy with axillary lymph node dissection between December 1998 and August 2001. About 73 percent received adjuvant hormonal therapy and 28 percent received adjuvant chemotherapy. The gene expression profiles obtained by MammaPrint classified the patients as high- or low-genomic risk. The median follow-up was 7.1 years. RESULTS: Among the 102 patients, 20 (20%) were classified as low-genomic risk and 82 (80%) were classified as high-genomic risk. The probability of distant metastasis-free survival at five years was 100% for the low-risk group and 94% for the high-risk group. CONCLUSIONS: The 70-gene MammaPrint prognosis profile accurately identified Japanese breast cancer patients at low risk of developing recurrences. In fact, 100% of the individuals in the low-risk category remained metastasis-free for the duration of the observation period.
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Neoplasias da Mama/genética , Perfilação da Expressão Gênica , Análise de Sequência com Séries de Oligonucleotídeos , Axila , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Intervalo Livre de Doença , Feminino , Humanos , Japão , Metástase Linfática , Pessoa de Meia-Idade , Metástase Neoplásica , Valor Preditivo dos Testes , Receptores de Estrogênio/análise , Receptores de Progesterona/análiseRESUMO
Multistage carcinogenesis is an important concept in cancer biology. Each new stage is triggered by the acquisition of an additional genetic aberration, leading to clonal expansion of the cancer cell. The resulting tumor mass consists of cancer cells with all genetic aberrations, but may include precursor cells at some point of carcinogenesis. We analyzed six colorectal cancer tissues with APC, K-ras, and p53 mutations. From each sample, 40-50 areas (100x100x40microm) consisting only of cancer cells were microdissected, and genomic DNA was purified. Ratios of mutated and normal alleles were quantitated by the SNaPshot assay, a primer extension assay. In five tumor tissues, we identified cancer cell subpopulations corresponding to putative precursors, i.e., cells with mutations in one or two of the three genes. All samples were likely to be of monoclonal origin, and temporal sequences of the mutations could be deduced from the mutation patterns of putative precursors. The orders of mutation events were variable. However, the two carcinoma tissues accompanying adenoma regions started with the APC mutation, not contradicting the previous studies. The analysis also revealed considerable heterogeneity in allele ratios of one or two of the chromosomes. The current findings are promising to uncover the process of carcinogenesis directly from the tumor tissue of the patient.