RASSF1A hypermethylation in pretreatment serum DNA of neuroblastoma patients: a prognostic marker

Abstract

The tumour suppressor gene RASSF1A is known to be frequently silenced by promoter hypermethylation in neuroblastoma tumours. Here we explored the possible prognostic significance of aberrant promoter hypermethylation of RASSF1A in serum DNA samples of patients with neuroblastoma as a surrogate marker for circulating tumour cells. We analysed the methylation status of the RASSF1A gene in matched tumour and pretreatment serum DNA obtained from 68 neuroblastoma patients. Hypermethylation of RASSF1A in tumour samples was found in 64 patients (94%). In contrast, serum methylation of RASSF1A was observed in 17 patients (25%). Serum methylation of RASSF1A was found to be statistically associated with age X12 months at diagnosis (P ¼ 0.002), stage 4 (Po0.001) and MYCN amplification (Po0.001). The influence of serum RASSF1A methylation on prognosis was found to be comparable with that of the currently most reliable marker, MYCN amplification on univariate analysis (hazard ratio, 9.2; 95% confidence interval (CI), 2.8 -30.1; Po0.001). In multivariate analysis of survival, methylation of RASSF1A in serum had a hazard ratio of 2.4 (95% CI, 0.6 -9.2), although this association did not reach statistical significance (P ¼ 0.194). These findings show that the methylation status of RASSF1A in the serum of patients with neuroblastoma has the potential to become a prognostic predictor of outcome.

Regulation of RASSF1A in nasopharyngeal cells and its response to UV irradiation

“…Previous studies have reported hypermethylation of the 5′ CpG island of RASSF1A in all xenografts, most cell lines and primary tumors tested, suggesting that DNA methylation is likely a critical mechanism in inactivation of the RASSF1A gene (Lo et al, 2001;Misawa et al, 2009;Kwong et al, 2002;Puente et al, 2008). Methylation affects gene expression either directly by interfering with binding of transcription factors and/or indirectly by recruiting histone deacetylases, leading to gene inactivation.…”

The Clinical Utilization of Circulating Cell Free DNA (CCFDNA) in Blood of Cancer Patients

“…For these cases, aberrant hypermethylation of the DCR2 promoter of the serum DNA has been helpful in predicting prognosis, therapeutic efficacy, and detecting reoccurrence in (non MNA) neuroblastomas. Also, determination of the hypermethylation status of RASSF1A of serum DNA is another prognostic marker for the outcome in neuroblatoma patients [94–96]. …”

Genetic Factors Influencing the Risk and Clinical Outcome of Neuroblastoma

“…Similarly, methylation patterns in RASSF1 and CASP8 have been reported to be correlated, although the clinical significance of this association is yet to be established (Astuti et al, 2001;Lazcoz et al, 2006). More recently, a study examining the level of promoter hypermethylation of RASSF1 in serum DNA samples of patients with neuroblastoma found increased levels of RASSF1 hypermethylation associated with older age, stage 4 disease, and MYCN amplification (Misawa et al, 2009). These promising findings indicate that screening for methylation status of RASSF1 and other genes in patient serum at diagnosis may be further developed for use as a non-surgical prognostic predictor of neuroblastoma outcome.…”