Promoter hypermethylation of the RASSF1A gene predicts the poor outcome of patients with hepatoblastoma

Background. Despite the progress of therapy, about 25% ofpatients with hepatoblastoma succumb to the disease. Prognostic factors, as well as improved therapies, are needed for these patients. We investigated the incidence and clinical significance of genetic and epigenetic aberrations in hepatoblastoma. Procedure. beta-catenin mutation was analyzed by sequencing and promoter hypermethylation of the RASSF1A and SFRP genes by methylation-specific PCR after bisulfate treatment of DNA samples from 39 helpatoblastomas. Association of the clinical and biological features, including sex, age of patients, stage of the disease, the histological type, and the beta-catenin and RASSFIA status with overall survival was evaluated using univariate and multivariate analysis. Results. beta-catenin mutation and RASSFIA methylation were found in 22 (56.4%) and 15 (38.5%) of 39 hepatoblastomas, respectively, but SFRPs methylation was not found in any of them. RASSFIA and SFRPs were unmethylated in five adjacent normal liver tissues. Patients with a RASSFIA methylated tumor were older in age (>= 2 years, P = 0.036), at more advanced stages (P = 0.009), and had more frequent beta-catenin mutation (P < 0.001) and poorer outcome (P < 0.001) than those with a RASSFIA unmethylated tumor. While univariate analysis showed the prognostic significance of age, stage, the histological type, and the beta-catenin and RASSF1A status, multivariate analysis showed only the RASSFIA methylation status as an independent factor predicting outcome (relative risk, 10.51; 95% CI, 1.21 similar to 90.97; P = 0.033). Conclusions. RASSFIA methylation may be a novel molecular-genetic marker for treatment outcome in hepatoblastoma if confirmed by studies examining a larger number of hepatoblastomas.