Endocrine Abstracts

Purpose: Papillary thyroid cancer (PTC) accounts for approximately 80% of all thyroid cancers and is defined by its unique cytologic and histologic features. Mutations of the RET and BRAF/V600 genes are found in nearly 70% of PTC cases. They are able to trigger the activation of mitogen-activated protein kinase pathways and to promote neoplastic cell proliferation. Genetic events may further lead to numerous different cell variants of PTC which may be identified via the different cyto/histopathologic features. The most common are the classical (CV), tall cell (TCV) and follicular variant (FV). The aim of the study was to perform the genomyc analysis of the RET and BRAF (V600) mutations in patients with PTC as well as to compare the obtained results with clinical findings.

Methods: The study included 112 patients diagnosed with PTC, aged 41-74 years. Mutations of the RET and BRAF (V600) genes were detected using Real-time polymerase chain reaction. Diagnosis of the PTC and its variants was confirmed with cyto/histopathological examination.

Results: The most important genomic, cyto/histopathological and prognostic elements regarding all three variants of the PTC are as follows: CV-PTC (n= 78): RET and BRAF (V600) mutations are common findings, with BRAF (V600) confirming a worse prognosis. The 65% of these patients have shown stabile disease course, with 25% with metastatic nodes; TCV-PTC (n= 8): Aggressive behavior has been attributed to BRAF (V600) mutation; FV-PTC (n= 26): Absence of BRAF (V600) mutation was the most important genetic element.

Conclusions: In most cases, PTC has an excellent prognosis, but certain variants express more aggressive clinical course. CV-PTC: BRAF (V600) mutation was negative prognostic element; TCV-PTC presents mostly in older patients, has agreater propensity for locoregional dissemination and has more aggressive course than CV-PTC; The prognosis of FV-PTC has been similar to that of CV-PTC. The patients with CV-PTC and FV-PTC had fovorable clinical course comparing to those with TCV-PTC. Our study suggests that PTC is etiopathogenically complex disease and requires further molecular investigations.