Neuroblastoma arises from the primitive neural crest cells, and is a common malignancy in childhood. The clinical features are characterized by biological heterogeneity. Neuronal degeneration and differentiation occur in some patients. However treatment in the high risk group accounting for approximately half, has not been satisfactory despite a multimodal approach. Therefore, effective treatment is determined by the risk group of prognostic factors, such as age at diagnosis, stage of disease, pathological finding and N-myc amplification. Neuroblastoma can be diagnosed prenatally, which suggests its origin during the normal embryogenesis. Recent knowledge of molecular biology, such as Trk genes, and the concept of cancer stem cells have given us some improved understanding on this disease. Currently, targeted therapies based on the molecular biology of neuroblastoma are under investigation and increasing survival rate and decreasing late complications could be appreciated.

Hepatoblastoma is a rare pediatric malignancy which frequently presents at an advanced unresectable stage. With the neoajuvant chemotherapy, improved resectability and survival have been reported. Twenty children with biopsy proven hepatoblastoma were treated during the period between January 1987 and June 1995. Median age at diagnosis was 13 months(2 months to 7 year and 10 months), and 13 were male. Histologic profile was 13 epithelia1(5 fetal, 4 mixed, 1 embryonal, 3 undetermined), and 5 mixed mesenchymal and epithelial and 2 of undetermined type. Chemotherapy effectively reduced the tumor volume(p=0.008), and' was able to convert 7 out of 9 initially unresectable cases(78%) to resectable ones. Twelve radical and 2 palliative operations were done with or without adjuvant chemotherapy. The Median follow up period was 33 months and the median survival was 26 months. The group with curative resection had a 61.1 % 5 year survival rate, but none of palliative resection grpup survived more than 13 months(p=0.000l). In univariate analysis for prognostic factors revealed, large tumor size at diagnosis and abscence of thrombocytopenia were associated with poor survival, but these differences were not statistically significant. Histological pure fetal type did not mean a better prognosis. Even with a recent neoadjuvant chemotherapy, the strategy should be focused on the radical resection as early as possible.