Genetic markers in thyroid tumors.

Tissue from nine patients with malignant tumors and two with benign tumors was cultured briefly before cytogenetic analysis. The tumors included one goiter and one Hürthle cell adenoma, one lymphoma, one medullary carcinoma, two Hürthle cell cancers, and five papillary cancers, varying widely in clinical staging and histologic differentiation. When assessed, DNA content was aneuploid in two of six malignant tumors. Various culture conditions (oxygen levels, dissociation methods, and media) were evaluated; the end points were growth, cell differentiation, and time to first harvest. Clonal aberrations were detected in one of four successfully harvested papillary cancers: they consisted of trisomy 7 and a rearrangement of chromosome 10. The rea (10) seen in 22 of 27 cells involved bands q11-21. Two other papillary tumors and a medullary cancer (a family member with multiple endocrine neoplasia type IIA) showed tetraploidy and nonclonal numerically aberrant cells. A lymphoma and two benign lesions showed no cytogenetic abnormality. The tumor with rea (10) is of special interest because abnormalities of 10q have been reported repeatedly in thyroid tumors, including two cases of papillary thyroid tumors with a structural aberration similar to that of the presented case. This rearrangement could affect the ret-proto-oncogene, localized to 10q11.2 which is activated in some papillary thyroid carcinomas.