RESUMEN
In the development and progression of cancer, tumor suppressor genes may be silenced by mechanisms such as methylation. Thus the discovery of new genes silenced by methylation may uncover new tumor suppressor genes, and improve our understanding of cancer biology. In this study we investigated the methylation of 19 genes in esophageal squamous cell carcinoma. Methylation was measured in 10 of these genes in esophageal squamous cell carcinoma cell lines: CDH13, CLDN6, C16orf62, FBN2, FNBP1, ID4, RBP1, RBP4, TFPI2 and TMEFF2. To determine if there was a correlation between DNA methylation and gene silencing, each cell line was cultured with or without the demethylating drug 5-aza-2'-deoxycytidine (aza-dC). For 6 genes (CLDN6, FBN2, RBP1, RBP4, TFPI2 and TMEFF2) there was an association between reduction of methylation and increase in mRNA expression in the demethylated cell lines. The frequency of the methylation of these 6 genes in esophageal squamous cell carcinoma resection specimens was also investigated. All 6 genes showed more frequent methylation in the tumor than the matched proximal resection margin of uninvolved esophagus. There was a significant difference in the frequency of methylation and in the extent of the methylation between the cancer and the margin tissues for CLDN6, FBN2, TFPI2 and TMEFF2 (P=0.0007, P=0.0048 P=0.0002 and P<0.0001, respectively). This is the first report of gene silencing by methylation of CLDN6, FBN2, RBP4, TFPI2 and TMEFF2 in esophageal squamous cell carcinoma.
Asunto(s)
Carcinoma de Células Escamosas/genética , Metilación de ADN , Neoplasias Esofágicas/genética , Glicoproteínas/genética , Proteínas de la Membrana/genética , Proteínas de Microfilamentos/genética , Proteínas de Neoplasias/genética , Proteínas Celulares de Unión al Retinol/genética , Proteínas Plasmáticas de Unión al Retinol/genética , Línea Celular Tumoral , Claudinas , Fibrilina-2 , Fibrilinas , Silenciador del Gen , HumanosRESUMEN
BACKGROUND: Metallothionein 3 (MT3) inhibits growth in a variety of cell types. We measured MT3 gene expression by RT-PCR, and DNA methylation in the MT3 promoter by combined bisulphite restriction analysis, in four oesophageal cancer cell lines and the resected oesophagus from 64 patients with oesophageal squamous cell carcinoma (SCC). RESULTS: MT3 expression was not detected in one of the four oesophageal cell lines. The MT3 promoter was methylated in all of the oesophageal cell lines, but the degree of methylation was greater in the non-expressing cell line. After treatment with 5-aza-2'-deoxycytidine there was a reduction in the degree of methylation, and an increase in MT3 expression, in each of the cell lines (p < 0.01). Methylation was detected in 52% (33 of 64) of primary SCC and 3% (2 of 62) of histologically normal resection margins. MT3 expression was measured in 29 tumours, 17 of which had methylation of MT3. The expression of MT3 was significantly less in the methylated tumours compared to either the unmethylated tumours (p = 0.03), or the matched margin (p = 0.0005). There was not a significant difference in MT3 expression between the tumour and the margin from patients with unmethylated tumour. No correlations were observed between methylation of MT3 and survival time, patient age, gender, smoking or drinking history, tumour stage, volume, or lymph node involvement. CONCLUSION: We conclude that MT3 expression is frequently down-regulated in oesophageal SCC, by DNA methylation, but that this is not a prognostic indicator.
Asunto(s)
Carcinoma de Células Escamosas/metabolismo , Metilación de ADN , Regulación hacia Abajo , Neoplasias Esofágicas/metabolismo , Regulación Neoplásica de la Expresión Génica , Proteínas del Tejido Nervioso/metabolismo , Adulto , Anciano , Carcinoma de Células Escamosas/genética , Línea Celular , Regulación hacia Abajo/efectos de los fármacos , Neoplasias Esofágicas/genética , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Linfocitos/metabolismo , Masculino , Metalotioneína 3 , Persona de Mediana Edad , Proteínas del Tejido Nervioso/genética , Regiones Promotoras Genéticas/genéticaRESUMEN
OBJECTIVES: Bronchoplastic and pulmonary arterioplastic procedures have become increasingly popular in recent years as an alternative to pneumonectomy, especially for patients with compromised cardiopulmonary reserve. We reviewed our experience with the procedure to determine the operative technique, indication for the procedure and long-term results. METHODS: From January 1981 to December 2000, 65 bronchoplasties, four pulmonary arterioplasties and three combined broncho-angioplasties were performed for bronchogenic carcinoma. RESULTS: Of the 72 patients, 31 had stage I disease, 29 had stage II and 12 had stage III disease. One patient (1.4%) died of bilateral pneumonitis postoperatively. Atelectasis occurred in two patients (2.8%), empyema in one (1.4%), and bronchial fistula in one (1.4%). There were no bronchial stenoses after bronchoplastic procedures, and no vascular complications after angioplastic procedures. The 1-, 3- and 5-year survival rates for the entire group were 86.0%, 47.0% and 29.8%, respectively. The difference in survival was significant between stage I and II disease (p=0.0001) and between stage I and III disease (p<0.0001), but not between stage II and III disease (p=0.0779). CONCLUSIONS: Bronchoplastic, pulmonary arterioplastic and broncho-angioplastic procedures can be performed safely. Bronchoplastic procedures offer patients with bronchogenic carcinoma a long-term result comparable to that with radical lung resection. Angioplastic and combined broncho-angioplastic procedures should only be used in patients who cannot tolerate pneumonectomy due to poor cardiopulmonary reserve.