Frequent occurrence of cytogenetic abnormalities in sporadic nonmedullary thyroid carcinoma.

Cytogenetic studies may provide important clues to the molecular pathogenesis of thyroid neoplasia. Thus, the authors attempted cytogenetic studies on 12 thyroid carcinomas: seven papillary, three follicular, and two anaplastic. Successful cytogenetic results were obtained on all 12 tumors; nine (75%) had one or more chromosomally abnormal clones. Four of the papillary carcinomas had a simple clonal karyotype, and three had no apparent chromosome abnormality. All four abnormal papillary tumors contained an anomaly of a chromosome 10q arm. In one instance, an inv(10)(q11.2q21.2) was observed in a Grade 2 papillary carcinoma as the sole acquired abnormality. In another case, an inversion or insertion involving 10q21.2 was found in a Grade 1 papillary tumor. The karyotype of a third tumor, a Grade 1 papillary carcinoma, was 46,XX,der(5)t(5;10)(p15.3;q11),der(9)t(9;?)(q11;?). A fourth abnormal papillary carcinoma, a Grade 1 tumor, had a t(6;10)(q21;q26.1) as the sole abnormality. Each of the five follicular or anaplastic carcinomas had a complex clonal karyotype. The three follicular carcinomas contained an abnormality of 3p25-p21, along with several other chromosome abnormalities.