Loss of heterozygosity (LOH) of the MTS1 (p16) tumor suppressor gene has been reported
to occur frequently in thyroid cancer cell lines. In order to determine the frequency
of LOH for these multiple tumor suppressor genes, we used micro-satellite markers
IFNA and D9S171 to perform differential quantitative polymerase chain reaction. Tumor
DNA was isolated from native sections of tumor tissue. Control DNA was isolated from
blood. PCR products were separated on 6% polyacrylamide sequencing gels and quantified
according to peak height and area. Analysis was informative in 70% of cases for both
markers, and in 88% for at least one out of both. LOH was found in 3 out of 35 informative
patients (8.6%) with papillary thyroid cancer, in 1 out of 7 patients with follicular
thyroid cancer (14.2%), and in 0 out of 18 medullary cancers (0%). No LOH was found
in 11 informative patients with multinodular goitre, 7 with follicular adenoma, 4
with Graves' disease, and 6 with other thyroid disease. 75% of LOH was found in T1
and T2 stages, it was not more frequent in patients with lymphonodular metastasis.
The low frequency of LOH in these types of thyroid cancer argues against a role of
loss of heterozygosity at the MTS 1 and 2 gene locus in the development of differentiated
thyroid neoplasia.
Key words
MTS1 - MTS2 - p15 - p16 - LOH - Thyroid - Cancer - IFNA - D9S171
