Frequent clonal chromosomal changes in human non-malignant tumors.

A cytogenetic analysis has been performed on 109 non-malignant human solid tumors of various histological types after short-term culture. These tumors were derived from epithelial, mesenchymal, embryonal and neurogenic tissues. The chromosome count was in the diploid range in virtually all specimens. Clonal chromosomal changes were found in 37% of tumors: 20% had numerical deviations, 12% structural rearrangements, and 5% both karyotypic alterations. Chromosome 7 was most frequently involved in 25% of abnormal specimens. Our results suggest that chromosomal changes contribute to non-malignant tumorigenesis and that their analysis may provide information about the genetic events which shift benign tumor cells to malignant behavior.