Karyotypic analyses of hepatoblastoma. Report of two cases and review of the literature suggesting chromosomal loci responsible for the pathogenesis of this disease.

Two cases of fetal hepatoblastoma with unique karyotypic changes are described. One was a 17-month-old boy with multiple unbalanced chromosomal translocations, resulting in four types of derivative chromosomes involving chromosomal loci at 1q21, 1q32, 2q23, 6q27, 7p22, and 21p12, partial tetrasomy of 1q, partial trisomy of 2q, and partial monosomy of 21p. The clonal karyotype of this tumor was 46,XY,der(2)t(1;2)(q32;q37), der(6)t(1;6)(q12;q27), der(7)t(2;7)(q23;p22), der(21)t(2;21) (q23;p12). In the other case, a 4-year-old girl, karyotypic analyses revealed trisomy 2 and 8, and the clonal karyotype of this case was 48,XX,+2,+8. Review of these cases together with previous reports suggested the significance of chromosomal changes including numerical abnormalities of 1q, 2(or 2q), 20, and 8 (or 8q), and breakage of 1q and 2q in the development of hepatoblastoma. The results presented herein underscore the significance of numerical abnormalities of chromosomal regions 1q and 2q and of chromosome 8 in the development of hepatoblastoma, in addition to abnormalities of 6q27, 7p22, and 21p12-13 as other chromosomal loci that may be responsible for the pathogenesis of this embryonal type of tumor.