Promoter hypermethylation of the RASSF1A gene predicts the poor outcome of patients with hepatoblastoma.
BACKGROUND
Despite the progress of therapy, about 25% of patients 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.


METHODS
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 hepatoblastomas. Association of the clinical and biological features, including sex, age of patients, stage of the disease, the histological type, and the beta-catenin and RASSF1A status with overall survival was evaluated using univariate and multivariate analysis.


RESULTS
beta-catenin mutation and RASSF1A 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. RASSF1A and SFRPs were unmethylated in five adjacent normal liver tissues. Patients with a RASSF1A methylated tumor were older in age (>or=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 RASSF1A 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 RASSF1A methylation status as an independent factor predicting outcome (relative risk, 10.51; 95% CI, 1.21 approximately 90.97; P=0.033).


CONCLUSIONS
RASSF1A methylation may be a novel molecular-genetic marker for treatment outcome in hepatoblastoma if confirmed by studies examining a larger number of hepatoblastomas.
Sugawara
Waka
W
Research Institute for Clinical Oncology, Saitama Cancer Center, Ina, Saitama, Japan.
Haruta
Masayuki
M
Sasaki
Fumiaki
F
Watanabe
Naoki
N
Tsunematsu
Yukiko
Y
Kikuta
Atsushi
A
Kaneko
Yasuhiko
Y
D048868:Adaptor Proteins, Signal Transducing; D000293:Adolescent; D044466:Asian People / Q000235:genetics*; D014408:Biomarkers, Tumor / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics; D005260:Female; D020868:Gene Silencing; D018197:Hepatoblastoma / Q000208:ethnology / Q000235:genetics* / Q000401:mortality; D006801:Humans; D007223:Infant; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D007564:Japan / Q000453:epidemiology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D015999:Multivariate Analysis; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics; D015996:Survival Rate; D025521:Tumor Suppressor Proteins / Q000235:genetics*; D051176:beta Catenin / Q000235:genetics; D000094742:Secreted Frizzled-Related Proteins
D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D005136:Eye Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins; D051176:beta Catenin; C411762:RASSF1 protein, human; C117636:SFRP1 protein, human; D000094742:Secreted Frizzled-Related Proteins; C109618:SFRP2 protein, human; C118723:SFRP4 protein, human; C118511:SFRP5 protein, human