Overexpression of wild-type c-RET and zero prevalence of RET/PTC rearrangements are associated with papillary thyroid cancer (PTC) in Kuwait.
BACKGROUND
Papillary thyroid carcinoma (PTC) is common in Kuwait. The activation of the RET oncogene by DNA rearrangement (RET/PTC) is known to have an important role in PTC carcinogenesis. However, the real frequency of the RET/PTC expression in PTC is variable between different studies. This study seeks to determine the prevalence of RET/PTC and to analyze the RET oncogene expression associated with PTC in Kuwait.


METHODS
RET expression and DNA rearrangements (RET/PTC 1, RET/PTC 2 and RET/PTC 3) were studied by RT-PCR in different thyroid diseases. Results were confirmed by the Southern blot and by immunohistochemistry. Quantitative real-time PCR was used to determine the level of RET mRNA expression in PTCs.


RESULTS
Wild-type (nonrearranged) c-RET oncogene was overexpressed in 60% of PTC cases and absent in follicular thyroid carcinoma (FTC), anaplastic thyroid carcinoma (ATC), follicular adenomas (FA) or normal thyroid. No RET/PTC rearrangement was detected in any sample. The c-RET expression in Hashimoto's thyroiditis and multinodular goiter was limited to follicular cells with PTC-like nuclear changes.


CONCLUSIONS
The overexpression of wild-type c-RET is a characteristic molecular event of PTCs in Kuwait. The prevalence of RET/PTC is zero and among the lowest recorded in the world.
El-Abdallah
Abir A
AA
Department of Pathology, Faculty of Medicine, Kuwait University, Safat 13110, PO Box 24923, Kuwait. abeer.a@hsc.edu.kw
Junaid
Thamradeen A
TA
D002277:Carcinoma; D002291:Carcinoma, Papillary; D015321:Gene Rearrangement; D006801:Humans; D007730:Kuwait; D015995:Prevalence; D051096:Proto-Oncogene Proteins c-ret / Q000032:analysis / Q000235:genetics*; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016606:Thyroid Nodule / Q000235:genetics; D013967:Thyroiditis, Autoimmune / Q000235:genetics
D051096:Proto-Oncogene Proteins c-ret