VE1 immunocytochemistry in thyroid FNAC as a screening test for BRAF mutations is highly specific for malignant category cases but can be suboptimal due to its high false-positive rate for the nonmalignant cases.

Background: Hepatocyte growth factor (HGF) is known to induce scattering in various epithelial cells, and E-cadherin plays important roles in the maintenance of cell-cell adhesion. However, the mechanisms surrounding these actions are not fully understood. Therefore, we examined how HGF affects the expression and distribution of E-cadherin. In addition, we observed the relationship between prognosis and modulation of E-cadherin by HGF in hypopharyngeal carcinoma.Methods: Tumor tissues from 66 patients with hypopharyngeal squamous cell carcinoma were evaluated for the expression of HGF, its receptor (c-Met), and E-cadherin. Reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot test were performed on hypopharyngeal cancer tissues. The association and changes of E-cadherin with HGF treatment in a hypopharyngeal cancer cell line were investigated by RT-PCR, Western blot analysis, inhibition assay, immunofluorescence staining, and invasion assay.Results: E-cadherin expression was found in 87.9% of squamous cell carcinomas; these could be further classified as membranous type (46.9%) or nonmembranous type (53.1%). The expression of HGF in tumors with nonmembranous type E-cadherin expression was far higher than in tumors with membranous expression. Nonmembranous type E-cadherin expression correlated significantly with lymph node metastasis, distant metastasis, and recurrence (P < .05). HGF decreased the expression of E-cadherin and induced the translocation of Ecadherin to the cytoplasm. HGF and E-cadherin neutralizing antibody stimulated dispersion, and HGF significantly enhanced the invasion of hypopharyngeal cancer cells in a dosedependent manner (P < .05).Conclusions: These results suggest that HGF can modulate the expression and intracellular localization of E-cadherin in hypopharyngeal cancer cells. In addition, these results indicate that changes in E-cadherin by HGF can affect the prognosis of hypopharyngeal carcinoma.

B-RafV600E mutant is found in 40–70% of papillary thyroid carcinoma (PTC) and has an important role in the pathogenesis of PTC. The sodium iodide symporter (NIS) is an integral plasma membrane glycoprotein that mediates active iodide transport into the thyroid follicular cells, and B-RafV600E has been known to be associated with the loss of NIS expression. In this study, we found that B-RafV600E inhibited NIS expression by the upregulation of its promoter methylation, and that specific regions of CpG islands of NIS promoter in B-RafV600E harboring PTC were highly methylated compared with surrounding normal tissue. Although DNA methyltransferase 3a and 3b (DNMT3a,3b) were not increased by B-RafV600E, DNMT1 expression was markedly upregulated in PTC and B-RafV600E expressing thyrocytes. Furthermore, DNMT1 expression was upregulated by B-RafV600E induced NF-κB activation. These results led us to conclude that NIS promoter methylation, which was induced by B-RafV600E, is one of the possible mechanisms involved in NIS downregulation in PTC.

No abstract

Background Assessing nuclear features is diagnostically challenging in the aspect of thyroid pathology. The aim of this study was to determine whether pathologists could distinguish BRAF -like and RAS -like nuclear features morphologically and identify morphological features to differentiate thyroid tumors with RAS -like mutations from encapsulated papillary thyroid carcinoma (PTC) with predominant follicular growth and BRAF V600E mutation. Methods Representative whole slide images of 16 encapsulated thyroid tumors with predominant follicular growth were reviewed by 12 thyroid pathologists using a web browser-based image viewer. Total nuclear score was calculated from semi-quantitatively scored eight nuclear features. The molecular profile of RAS and BRAF genes was determined by Sanger sequencing. Results Total nuclear score ranging 0 to 24 could differentiate BRAF -like tumors from RAS -like tumors with a cut-off value of score 14. The interobserver agreement was the highest for the assessment of nuclear pseudoinclusions (NPIs) but the lowest for nuclear elongation and sickle-shaped nuclei. NPIs were found in tumors with BRAF V600E mutation, but not in tumors with RAS -like mutations. Total nuclear scores were significantly higher for tumors with BRAF V600E than for those with RAS -like mutations ( P <0.001). Conclusion Our results suggest that NPIs and high nuclear scores have diagnostic utility as rule-in markers for differentiating PTC with BRAF V600E mutation from benign or borderline follicular tumors with RAS -like mutations. Relaxation of rigid criteria for nuclear features resulted in an overdiagnosis of PTC. Immunostaining or molecular testing for BRAF V600E mutation is a useful adjunct for cases with high nuclear scores to identify true PTC.