Flow cytometric evaluation of nuclear DNA content in hepatoblastoma: further evidence for the inhomogeneity of the different subtypes.

The DNA ploidy pattern of nine hepatoblastomas and three normal liver specimens was investigated by flow cytometry. Areas of unlike differentiation in the same tumor were investigated separately. Normal liver tissue and the fetal subtype were always diploid. Aneuploidy was found in the embryonal subtype. The one case of small cell tumor was also diploid. When the fetal and embryonal areas of the same tumor were analyzed together, there was always an aneuploid peak in the histogram. There are obvious differences in DNA ploidy among the various hepatoblastoma subtypes. Differences in methods used, including the failure in some studies to evaluate areas of unlike differentiation in the same tumor separately, probably account to some extent for the conflicting results of previously reported studies. When flow cytometric analysis of the DNA content of a hepatoblastoma is performed, it is important to ensure that the various types of differentiation in the tumor are represented adequately in the material investigated, especially when conclusions about the prognosis are to be based on these findings.