To test this hypothesis, we examined thyroid tissue from 27 consecutive autopsy cases for the presence of CCH (defined as >50 C-cells/x100 magnification in three fields) and for AR expression in autopsy cases and in 43 medullary thyroid carcinomas (MTCs) from patients with sporadic and familial disease as well as two multiple endocrine neoplasia type 2A patients with only CCH.
In order to determine the clonal origin of sporadic MTCs and of those occurring in MEN 2 syndromes we used a clonality assay based on a polymorphic trinucleotide repeat of the X-linked human androgen-receptor gene.