[Analysis of tumour-derived DNA in serum in advanced non-microcytic lung cancer: might it be a prognostic factor?]. / Análisis de la concentración sérica del ADN tumoral en el cáncer de pulmón no microcítico y avanzado: 'es útil como factor pronóstico?

INTRODUCTION: Presence of circulating DNA in the serum of patients with cancer makes detection of tumour-specific genetic alterations feasible. OBJECTIVE: To study serum DNA concentration in patients diagnosed as having advanced Non-Small Cell Lung Cancer (NSCLC) and to evaluate its relationship with age, histology, stage, response, time-to-progression (TTP), and survival. METHODS: Serum DNA from 78 patients was purified and spectrophotometrically quantified. RESULTS: No significant correlations were found between serum DNA concentration and age, histology, response and survival. There was a significant correlation with respect to stage (IIIB = 408.75 ng/ml; IV = 478.74 ng/ml; p = 0.02). When patients were grouped according to DNA concentration, significant correlation with TTP was found; establishing a cut-off point at 500 ng/ml ([DNA] < 500 ng/ml TTP = 7.25 months, 95%CI: 3.5-5.25; [DNA ] > or = 500 ng/ml TTP = 4.25 months, 95%CI: 2-6.5; p = 0.05). CONCLUSIONS: Using the present method, DNA concentration quantification appears to be simple, but with certain deficiencies due to inter-sample variability and low specificity. This is because total DNA concentration is measured without distinguishing as to whether it is tumour-related. We suggest that there is a correlation between DNA concentration and prognosis which enables an analysis of the natural history of the disease.

Análisis de la concentración sérica del ADN tumoral en el cáncer de pulmón no microcítico y avanzado: ¿es útil como factor pronóstico? / Analysis of tumour-derived DNA in serum in advanced non-microcytic lung cancer: might it be a prognostic factor?

Introducción. El ADN sérico de pacientes oncológicos puede permitir detectar alteraciones genéticas específicas del tumor. Objetivo. Estudiar la concentración de ADN sérico ([ADN]) en pacientes con cáncer de pulmón no microcítico (CPNM) avanzado. Evaluar su relación con la edad, histología, estadio, respuesta, tiempo a la progresión (TTP) y supervivencia. Métodos. Se purificó el ADN sérico de 78 pacientes y se cuantificó espectrofotométricamente. Resultados. No hubo diferencias significativas entre [ADN] media y edad, histología, respuesta, y supervivencia. Hubo significatividad respecto al estadio (IIIB= 408,75 ng/ml; IV= 478,74 ng/ml; p= 0,02). Agrupando los pacientes según el [ADN] hubo significatividad en TTP estableciendo un punto de corte en 500 ng/ml ([ADN] = 500 ng/ml, TTP=4,25 meses, IC 95% 2-6,5; p= 0,05). Conclusiones. La cuantificación del ADN sérico resulta sencilla mediante este método, pero presenta deficiencias debido a la variabilidad intermuestral y a la baja especificidad, al medirse el [ADN] total sin especificar su asociación o no al tumor. Nuestro estudio sugiere que el [ADN] está relacionado con el pronóstico permitiendo un análisis evolutivo

Introduction. Presence of circulating DNA in the serum of patients with cancer makes detection of tumour-specific genetic alterations feasible. Objective. To study serum DNA concentration in patients diagnosed as having advanced Non-Small Cell Lung Cancer (NSCLC) and to evaluate its relationship with age, histology, stage, response, time-to-progression (TTP), and survival. Methods. Serum DNA from 78 patients was purified and spectrophotometrically quantified. Results. No significant correlations were found between serum DNA concentration and age, histology, response and survival. There was a significant correlation with respect to stage (IIIB = 408.75 ng/ml; IV = 478.74 ng/ml; p = 0.02). When patients were grouped according to DNA concentration, significant correlation with TTP was found; establishing a cut-off point at 500 ng/ml ([DNA] = 500 ng/ml TTP = 4.25 months, 95%CI: 2-6.5; p = 0.05). Conclusions. Using the present method, DNA concentration quantification appears to be simple, but with certain deficiencies due to inter-sample variability and low specificity. This is because total DNA concentration is measured without distinguishing as to whether it is tumour-related. We suggest that there is a correlation between DNA concentration and prognosis which enables an analysis of the natural history of the disease