- To detect histologic and molecular differences separating NIFTP from follicular adenomas (FAs) and invasive carcinomas, particularly papillary carcinomas with extensive follicular growth (PTC-EFGs) and invasive encapsulated PTC-FV (IE-PTC-FV).
Papillary carcinomas show frequently a specific gene rearrangement which gives rise to the formation of several types of so-called RET/PTC chimeric genes.
Assessment of RET/PTC oncogene activation and clonality in thyroid nodules with incomplete morphological evidence of papillary carcinoma: a search for the early precursors of papillary cancer.
Chromosomal rearrangements involving the RET gene, known as RET/PTC, are prevalent in thyroid papillary carcinomas from patients with radiation history.
Employing in situ hybridization to detect INSL-3 transcripts and specific rabbit antisera against the INSL-3 proteins, both INSL-3 isoforms were detected in patients with Graves' disease (n=10), follicular carcinomas (FTC; n=12), papillary carcinomas (PTC; n=9) and undifferentiated anaplastic carcinomas (UTC; n=15).
Here we report that ret/ptc1 oncogene was activated in two of the three papillary carcinomas of FAP kindred 1 and in the papillary carcinoma of FAP kindred 2.
In addition, the activation of PLD by pervanadate triggered phosphorylation of tyrosine 705 residue on STAT-3, and its phosphorylation was dramatically higher in TPC-1 cells (from papillary carcinoma) that have an endogenous RET/PTC1 than in ARO cells (from anaplastic carcinoma) without alteration of total STAT-3 expression.
In contrast, in thyroid carcinomas with single component histology, RET/PTC1 was detected in 11% of PCs and in none of the UCs, and RET/PTC3 was not found in any of the tumours studied.
In fact, it has been demonstrated that: a) RET/PTC is an early event in the process of thyroid carcinogenesis and has a critical role in the generation of the papillary carcinoma; b) RET/PTC activation is essentially restricted to the papillary histotype and to the Hürthle thyroid tumors; c) its incidence increases after exposure to radiations.
Our results indicate that: 1) the overall frequency of ret rearrangements was 84% in papillary carcinomas (16/19) and 45% (9/20) in follicular adenomas; 2) in contrast with the results obtained in the Chernobyl tumors, the most frequently observed chimeric gene was RET/PTC1; and 3) all the tumors were negative for RET/PTC2.
RET rearrangements are restricted to a well-differentiated papillary carcinoma, suggesting that RET/PTC positive papillary carcinomas do not progress to undifferentiated carcinoma.
RET/PTC1 tends to be more common in tumors with typical papillary growth and microcarcinomas and to have a more benign clinical course, whereas RET/PTC3 in some populations shows a strong correlation with the solid variant of papillary carcinoma and more aggressive tumor behavior.
Taken together these results support the concept that RET/PTC activation plays a central role in the pathogenesis of thyroid papillary carcinomas in both Ukraine and Belarus after the Chernobyl accident.
The aim of this study was to investigate the frequency and types of PTC genetic rearrangements in papillary carcinoma in a population of Hong Kong Chinese.
The frequency, if we consider exclusively the papillary carcinomas, is in both cases 12%; (b) show that the TRK oncogene plays a role in the development of a minority of radiation-associated papillary thyroid carcinomas but not in adenomas; and (c) confirm that RET/PTC rearrangements are the major genetic alteration associated with ionizing radiation-induced thyroid tumorigenesis.
The identification of ret/PTC gene rearrangements refined the diagnosis of PC in 9 of 15 specimens (60%) that would otherwise have been considered indeterminate and in 2 of 6 that were considered insufficient for cytological diagnosis.