Cytogenetic characterization of childhood hepatoblastoma.

We describe the cytogenetic abnormalities in two cases of childhood hepatoblastoma. The first case was of fetal histology with squamous metaplasia, and cytogenetic study showed an add(5)(q31). Although an association between hepatoblastoma and familial adenomatous polyposis is recognized, the breakpoint in this case is distal to 5q21 and most probably does not involve the APC gene at that location. The second case was of macrotrabecular histology, and cytogenetic study showed an unbalanced translocation in the form of der(4)t(1;4)(q12;q34) in a hyperdiploid clone. Including our case, der(4)t(1;4)(q12;q34) has been recognized in four cases of hepatoblastoma, and it may be the first recurrent translocation in this tumor. Understanding the molecular mechanism and clinical significance of this translocation awaits analysis of more cases.