Further chromosome studies on Wilms' tumor cells of patients without aniridia.

We studied chromosomes in Wilms' tumor cells of two patients without aniridia who had a normal constitutional karyotype. In both tumors, trisomy for 1q occurred as the result of a t(1;16), although the breakpoints in each chromosome differed in the two tumors. No 11p rearrangements could be detected, whereas in our previous patient an interstitial deletion of 11p13 was present in all tumor cells. Thus, trisomy for 1q may be another pathway leading to the development of Wilms' tumor, although the effect of the deletion of 16q cannot be assessed at present.