Several single-nucleotide polymorphisms (SNPs) have been associated with papillary and follicular thyroid cancer (PTC and FTC, respectively) risk, but few have replicated.
The prevalence of the fusions was determined by RT-PCR in 71 classical PTC, 45 follicular variants of PTC (FVPTC), 19 follicular thyroid adenomas (FTAs) and 22 follicular thyroid carcinomas (FTCs).
This was a retrospective cross-sectional evaluation of 115 archived samples, including: 47 benign (29 follicular adenoma, 11 diffuse hyperplasia, four thyroiditis, and three multinodular goiter), six follicular thyroid carcinomas (FTC), 24 follicular variant of papillary thyroid carcinomas (fvPTC), 27 classic variant of PTC (cPTC), eight diffuse sclerosing variant of PTC (dsvPTC), and three other PTC.
German patients (n=253) with DTC (papillary thyroid carcinoma [PTC] and follicular thyroid carcinoma [FTC]) and HC (n=302) were genotyped for polymorphisms within the vitamin D metabolizing enzymes such as 25-hydroxylase (CYP2R1[rs12794714, rs10741657]), 25-hydroxyvitamin D-1α-hydroxylase (CYP27B1[rs10877012, rs4646536]), and 25-hydroxyvitamin D 24-hydrolase (CYP24A1[rs927650, rs2248137, rs2296241]).
We have developed a home-brew tetracolor break-apart probe able to simultaneously identify the 2 most common genetic alterations in differentiated thyroid carcinoma: RET/PTC variants in papillary thyroid carcinoma and PAX8/PPARg fusion and variants in follicular thyroid carcinoma.
Whether a limited surgical approach is also justified in other cases, e.g. in any patient with intrathyroidal PTC or patients with micro-FTC (follicular thyroid carcinoma), remains to be shown and is the subject of ongoing investigations.
The surgical resection specimen demonstrated FVPTC in 20 (74%) cases, classical type PTC in two (7%), solid variant of PTC in one (4%), and follicular thyroid carcinoma in four (15%).
Skeletal muscle metastasis of papillary or follicular thyroid cancer (PTC/FTC) is a rare finding; only 11 cases of skeletal muscle PTC or FTC metastasis have been included in medical literature reviews.
Based on the four possible outcomes (FTA, C-PTC, FV-PTC, and FTC), about 80% of FTA and C-PTC and 50% of FV-PTC and FTC samples were correctly assigned.
Histology was reviewed, and the patients were divided in the following three groups: poorly differentiated carcinoma [PDTC; group 1 (n = 27)]; papillary thyroid carcinoma with PDA [PTC with PDA; group 2 (n = 27)]; and follicular thyroid carcinoma with PDA [FTC with PDA; group 3 (n = 88)].
In conclusion, chromosomal abnormalities are frequent in ATCs associated with FTC, but uncommon in those associated with PTC and in ATCs with no associated differentiated thyroid cancer.