Cytogenetic study of cell lines from an infantile hypercalcemic renal tumor

Four cell lines were obtained in vivo and in vitro from an infantile hypercalcemic renal tumor, which is considered to be a new tumor entity. Biochemical characteristics of the cells, studied after heterotransplantation into nude mice, were similar to those observed in the original tumor. One of the two in vitro cell lines originated from the initial tumor, the other from transplanted tumors in nude mice. One of the two in vivo cell lines originated in nude mice from serial grafts of the initial tumor, the other from grafts of the first in vitro cell line. All cell lines showed a human diploid karyotype, except for the cell line obtained directly from the tumor. In the latter, the karyotypes showed either a regional duplication of the long arm of chromosome #5 or a duplication of the long arm of chromosome #21. These two rearrangements did not appear simultaneously in the same cells, and their frequencies changed at each passage. The study of these different cell lines showed a remarkable karyotype stability, which did not prevent successful grafting into nude mice.