Chromosome abnormalities in tumor cells from patients with sporadic Wilms' tumor

The karyotype of nine of 11 Wilms' tumors was successfully analyzed using chromosome banding techniques. Peripheral lymphocytes had a normal karyotype in all six analyzed cases. Cultured cells from one tumor had a normal karyotype; however, they appeared to be fibroblasts. A chromosome 11 deletion, del(11)(p13p14), similar to that seen in patients with sporadic aniridia, was found as the sole abnormality in cells from one tumor. Abnormalities of chromosome 1 resulting in trisomy for the long arm (q21-q31) were found in five cases. Two of them had a translocation involving 1q and 16q, although the breakpoints in each chromosome appeared to differ in the two cases. Two patients had an isochromosome of the long arm, i(1q), and a fifth case had a duplication of the long arm as a result of karyotypic evolution. Chromosome 16 abnormalities were found in three cases, resulting in the partial monosomy of the long arm, sharing q22 as a common deletion. The same three cases also had trisomy 1q due to an unbalanced translocation of 1q or an i(1q). Trisomy for both chromosomes 9 and 12 were present in three cases. Two patients each had whole or partial trisomy of chromosomes 6, 7, 8, 17, and 18. Our data show that although an 11p deletion can occur as a mutation confined to tumor cells, the most common changes are trisomy for 1q, and less often a deletion of 16q.