RESUMEN
BACKGROUND: Tumor-specific alterations of DNA methylation in circulating DNA have been associated with tumor burden and malignant progression. A wealth of information indicating the potential use of DNA methylation in circulating DNA for cancer screening, prognosis and monitoring of the efficacy of anticancer therapies has emerged. In this study, we examined prospectively whether the presence of plasma DNA with tumor characteristics before oesophagectomy is a predictive factor related to disease-free survival (DFS). METHODS: Promoter hypermethylation of MSH2 was analyzed using real-time methylation-specific PCR (real-time MSP) in paired tumor and plasma samples of 209 patients with esophageal squamous cell carcinoma (ESCC). RESULTS: Aberrant MSH2 methylation was found in 101 of 209 ESCC patients. Of these 101 patients, 77 cases exhibited the same alteration in their plasma DNA. No alterations were found in the plasma DNA of the remaining 108 patients. As a control, we screened for aberrant methylation in the plasma DNA of 60 health individuals. No methylation was found in plasma DNA of these control groups. Follow-up analysis indicated significantly lower DFS for patients with high MSH2 methylation compared to those with MSH2 unmethylation after surgery. CONCLUSIONS: It was suggestted that MSH2 methylation in the plasma would be a good predictor of DFS for these ESCC patients before oesophagectomy.
Asunto(s)
Biomarcadores de Tumor/sangre , Carcinoma de Células Escamosas/metabolismo , Metilación de ADN , Neoplasias Esofágicas/metabolismo , Proteína 2 Homóloga a MutS/sangre , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/genética , Carcinoma de Células Escamosas/mortalidad , Carcinoma de Células Escamosas/patología , Estudios de Casos y Controles , China , ADN/análisis , Cartilla de ADN , Supervivencia sin Enfermedad , Neoplasias Esofágicas/mortalidad , Neoplasias Esofágicas/patología , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Proteína 2 Homóloga a MutS/genética , Reacción en Cadena de la Polimerasa , Valor Predictivo de las Pruebas , Regiones Promotoras Genéticas , Estudios ProspectivosRESUMEN
PURPOSE: Temozolomide (TMZ) is an oral derivative of dacarbazine that induces DNA damage by methylating nucleotide bases. Resistance has been associated with high levels of O6-methylguanine-DNA methyltransferase (MGMT). Malignant CD4(+) T cells of patients with mycosis fungoides/Sézary syndrome (MF/SS) have been shown to have low levels of MGMT and may be particularly sensitive to this methylator. EXPERIMENTAL DESIGN: The efficacy of TMZ was evaluated in a multicenter phase II trial of patients with advanced stages of MF/SS. TMZ was given orally at daily doses of 200 mg/m² for 5 days every 28 days. MGMT and mismatch repair protein expression was assessed by quantitative immunofluorescence and immunohistochemistry in skin and blood samples. RESULTS: Twenty-six patients (stages IB-IVB) were evaluable for response. Patients had a median of four prior treatments. Median follow-up time was 19 months (range, 1-95). The overall response was 27% with two complete remissions (8%) and five partial remissions (19%). Median disease-free survival was 4 months. The median overall survival was 24 months. The most frequent toxicities included constitutional symptoms, gastrointestinal symptoms, and hematologic toxicities. Treatment was discontinued in three patients following grade 3 thrombocytopenia, lymphopenia, and skin reaction. The relationship between pretreatment MGMT and mutL homolog 1 (MLH1)/mutS homolog 2 (MSH2) mismatch repair protein expression levels in skin biopsies of cutaneous lesions and clinical response to TMZ were evaluated. CONCLUSIONS: Pretreatment levels of MGMT and MLH1/MSH2 protein levels are not predictive of response to TMZ in MF/SS, suggesting that other resistance mechanisms are important.
Asunto(s)
Antineoplásicos Alquilantes/uso terapéutico , Reparación de la Incompatibilidad de ADN/efectos de los fármacos , Dacarbazina/análogos & derivados , Micosis Fungoide/tratamiento farmacológico , O(6)-Metilguanina-ADN Metiltransferasa/metabolismo , Síndrome de Sézary/tratamiento farmacológico , Proteínas Adaptadoras Transductoras de Señales/sangre , Adulto , Anciano , Anciano de 80 o más Años , Antineoplásicos Alquilantes/administración & dosificación , Antineoplásicos Alquilantes/farmacología , Daño del ADN , Dacarbazina/administración & dosificación , Dacarbazina/efectos adversos , Dacarbazina/farmacología , Dacarbazina/uso terapéutico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Homólogo 1 de la Proteína MutL , Proteína 2 Homóloga a MutS/sangre , Proteínas Nucleares/sangre , Temozolomida , Resultado del TratamientoRESUMEN
Epidemiological studies indicated that the incidence of esophageal squamous-cell carcinoma (ESCC) is associated with exposure to a variety of environmental factors. To determine whether the baseline expression of genes involved in DNA damage and repair induced by these carcinogens is associated with higher risk for ESCC, a case-control study was undertaken and the relative expression levels of six DNA repair genes (MGMT, hOGG1, XRCC1, XPD, hMLH1, and hMSH2) were determined in peripheral blood mononuclear cells (PBMC). One hundred patients with newly diagnosed, untreated ESCC and 117 healthy controls matched for age, gender, and residence were recruited. Expression levels of six genes were measured by quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR). Compared with controls, the relative expression levels of hMLH1, hMSH2, XRCC1, XPD, and MGMT, were significantly altered in ESCC patients. Using the median of relative expression level in controls as the cutoff point, results also demonstrated an increased risk for ESCC associated with reduced expression of hMSH2, XRCC, XPD, and MGMT. The expression levels of four genes (hMSH2, XRCC1, XPD, MGMT) present in PBMC were significantly correlated with increased risk for ESCC, in which there was reduced expression of MGMT, suggesting an important etiology role for MGMT expression in the initiation of ESCC in Huaian of China.
Asunto(s)
Pueblo Asiatico/genética , Carcinoma de Células Escamosas/genética , Reparación del ADN/genética , Proteínas de Unión al ADN/genética , Neoplasias Esofágicas/genética , Predisposición Genética a la Enfermedad , Carcinoma de Células Escamosas/sangre , Estudios de Casos y Controles , China , Metilasas de Modificación del ADN/sangre , Metilasas de Modificación del ADN/genética , Enzimas Reparadoras del ADN/sangre , Enzimas Reparadoras del ADN/genética , Proteínas de Unión al ADN/sangre , Neoplasias Esofágicas/sangre , Femenino , Expresión Génica , Perfilación de la Expresión Génica , Humanos , Leucocitos Mononucleares , Masculino , Persona de Mediana Edad , Proteína 2 Homóloga a MutS/sangre , Proteína 2 Homóloga a MutS/genética , Oportunidad Relativa , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Proteínas Supresoras de Tumor/sangre , Proteínas Supresoras de Tumor/genética , Proteína 1 de Reparación por Escisión del Grupo de Complementación Cruzada de las Lesiones por Rayos X , Proteína de la Xerodermia Pigmentosa del Grupo D/sangre , Proteína de la Xerodermia Pigmentosa del Grupo D/genéticaRESUMEN
AIM: To detect the germline mutations of hMLH1 and hMSH2 based on mRNA sequencing to identify hereditary non-polyposis colorectal cancer (HNPCC) families. METHODS: Total RNA was extracted from peripheral blood of 14 members from 12 different families fulfilling Amsterdam criteria II. mRNA of hMLH1 and hMSH2 was reversed with special primers and heat-resistant reverse transcriptase. cDNA was amplified with expand long template PCR and cDNA sequencing analysis was followed. RESULT: Seven germline mutations were found in 6 families (6/12, 50%), in 4 hMLH1 and 3 hMSH2 mutations (4/12, 33.3%); (3/12, 25%). The mutation types involved 4 missense, 1 silent and 1 frame shift mutations as well as 1 mutation in the non-coding area. Four out of the seven mutations have not been reported previously. The 4 hMLH1 mutations were distributed in exons 8, 12, 16, and 19. The 3 hMSH2 mutations were distributed in exons 1 and 2. Six out of the 7 mutations were pathological, which were distributed in 5 HNPCC families. CONCLUSION: Germline mutations of hMLH1 and hMSH2 can be found based on cDNA sequencing so as to identify HNPCC family, which is highly sensitive and has the advantages of cost and time saving.