RESUMO
By comparative DNA fingerprinting, we identified a 357-bp DNA fragment frequently amplified in esophageal squamous cell carcinomas (ESCC). This fragment overlaps with an expressed sequence tag mapped to 7q22. Further 5' and 3'-rapid amplification of cDNA ends revealed that it is part of a novel, single-exon gene with full-length mRNA of 2052 bp and encodes a nuclear protein of 109 amino acids ( approximately 15 kDa). This gene, designated as gene amplified in esophageal cancer 1 (GAEC1), was located within a 1-2 Mb amplicon at 7q22.1 identified by high-resolution 1 Mb array-comparative genomic hybridization in 6/10 ESCC cell lines. GAEC1 was ubiquitously expressed in normal tissues including esophageal and gastrointestinal organs; with amplification and overexpression in 6/10 (60%) ESCC cell lines and 34/99 (34%) primary tumors. Overexpression of GAEC1 in 3T3 mouse fibroblasts caused foci formation and colony formation in soft agar, comparable to H-ras and injection of GAEC1-transfected 3T3 cells into athymic nude mice formed undifferentiated sarcoma in vivo, indicating that GAEC1 is a transforming oncogene. Although no significant correlation was observed between GAEC1 amplification and clinicopathological parameters and prognosis, our study demonstrated that overexpressed GAEC1 has tumorigenic potential and suggest that overexpressed GAEC1 may play an important role in ESCC pathogenesis.
Assuntos
Carcinoma de Células Escamosas/genética , Núcleo Celular/metabolismo , Cromossomos Humanos Par 7 , Neoplasias Esofágicas/genética , Regulação Neoplásica da Expressão Gênica , Proteínas Nucleares/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Carcinoma de Células Escamosas/metabolismo , Linhagem Celular Tumoral , Neoplasias Esofágicas/metabolismo , Humanos , Camundongos , Camundongos Nus , Modelos Genéticos , Dados de Sequência Molecular , Transplante de Neoplasias , Proteínas Nucleares/biossínteseAssuntos
Povo Asiático/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Análise Mutacional de DNA , Efeito Fundador , Testes Genéticos/métodos , Mutação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteínas Reguladoras de Apoptose , Neoplasias da Mama/etnologia , China , Éxons , Feminino , Predisposição Genética para Doença , Humanos , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Temperatura de Transição , Adulto JovemRESUMO
AIMS: Mutation of the KRAS gene predicts the clinical response to the monoclonal antibody cetuximab in patients with advanced colorectal cancer (CRC). This study aimed to perform KRAS mutation detection on formalin-fixed paraffin-embedded (FFPE) tumour tissue by two different methods for comparison. METHODS: The FFPE sample was microdissected to enrich for tumour cells. KRAS exon 2 mutations were performed on 100 Chinese patients with CRC by direct nucleotide sequencing and high-resolution melting (HRM) analysis. RESULTS: KRAS exon 2 mutations were detected in a total of 62 patients with the two methods combined, comprising 11 different mutant alleles. Three common mutations p.Gly12Asp, p.Gly12Val and p.Gly13Asp accounted for approximately 70% of all cases. The concordant rate between the two methods was 95%. Four mutations not initially detected by direct sequencing were identified by HRM and confirmed by sequencing of the HRM amplicons. One mutation detected by direct sequencing was inadvertently grouped as a wild-type allele by HRM software, but this was readily rectified through manual review. CONCLUSION: HRM analysis is a sensitive method of detecting KRAS mutation on FFPE tumour tissue to guide cetuximab treatment and is applicable to routine molecular diagnostic service. Utilisation of HRM to screen for mutations upfront economises the resource used in the sequencing reaction.
Assuntos
Neoplasias Colorretais/genética , DNA de Neoplasias/genética , Genes ras/genética , Mutação , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados , Antineoplásicos/uso terapêutico , Sequência de Bases , Cetuximab , Neoplasias Colorretais/tratamento farmacológico , Análise Mutacional de DNA/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Desnaturação de Ácido Nucleico , Inclusão em Parafina , Reprodutibilidade dos Testes , Temperatura de TransiçãoRESUMO
Breast cancers related to BRCA mutations are associated with particular biological features. Here we report the clinical and pathological characteristics of breast cancer in Chinese women with and without BRCA mutations and of carriers of BRCA1 mutations compared to BRCA2 mutations. Two hundred and 26 high-risk Hong Kong Chinese women were tested for BRCA mutations, medical information was obtained from medical records, and risk and demographic information was obtained from personal interviews. In this cohort, 28 (12.4%) women were BRCA mutation carriers and among these carriers, 39.3% were BRCA1 and 60.7% were BRCA2 mutations. Mutation carriers were more likely to have a familial history of breast and ovarian cancer, high-grade cancers, and triple negative (TN) cancers. Prevalence of TN was 48.3% in BRCA carriers and 25.6% in non-carriers and was 67.7% in BRCA1 and 35.3% in BRCA2 carriers. Estrogen receptor (ER) negative cancer was significantly associated with BRCA1 mutations, especially in those under 40 years of age. BRCA-related breast cancer in this Chinese population is associated with family history and adverse pathological/prognostic features, with BRCA2 mutations being more prevalent but BRCA1 carriers having more aggressive and TN cancers. Compared to Caucasian populations, prevalence of BRCA2 mutations and TN cancer in BRCA2 mutation carriers in Chinese population are elevated.