Chromosomal changes in thyroid tumors. Relation with DNA content, karyotypic features, and clinical data.

A cytogenetic study was performed in 63 thyroid tumors after a monolayer short-term culture. Clonal chromosomal changes were found in 47% of carcinomas and 31% of adenomas. Chromosome 7 was altered in 40% of cytogenetically abnormal tumors. The modal DNA index measured in 26 tumors was consistent with the chromosomal mode in 88% of cases. A quantitative morphometric analysis of nuclear features differentiated between diploid thyroid adenomas with or without a single translocation, which suggests that they have different biological properties. Clonal chromosomal changes were observed in 78% of carcinomas with an aggressive behavior, but only 28% of those had no risk factors. The two patients who died early had abnormalities of chromosome 7.