ABSENCE OF P53 GENE MUTATION AND INFREQUENT OVEREXPRESSION OF P53 PROTEIN IN HEPATOBLASTOMA

Ten cases of hepatoblastoma were studied for overexpression of p53 pro tein by immunohistochemistry and for possible p53 gene mutation by sin gle strand conformation polymorphism (SSCP) analysis and direct DNA se quencing of the polymerase chain reaction products. Only one case of t he macrotrabecular type at stage IV showed overexpression of p53 prote in. No DNA mobility shift was found in any of the cases studied by SSC P analysis. DNA sequencing performed on the case showing overexpressio n of p53 protein revealed no mutation within exons 5 to 8. The associa ted adrenal cortical carcinoma of the same case also showed overexpres sion of p53 protein, but no mutation of the p53 gene. These results in dicate that mutation of the p53 gene is infrequent in hepatoblastoma. This observation supports the view that mutation of the p53 gene is no t as important in the oncogenesis of childhood neoplasms as in adult c ancers.