Follicular Lesions with Papillary Nuclear Characteristics: Differences in Chromatin Detected by Computerized Image Analysis

ABSTRACT Objective: Follicular lesions of the thyroid with papillary carcinoma nuclear characteristics are classified as infiltrative follicular variant of papillary thyroid carcinoma-FVPTC (IFVPTC), encapsulated/well demarcated FVPTC with tumour capsular invasion (IEFVPTC), and the newly described category "non-invasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) formerly known as non-invasive encapsulated FVPTC. This study evaluated whether computerized image analysis can detect nuclear differences between these three tumour subtypes. Materials and methods: Slides with histological material from 15 cases of NIFTP and 33 cases of FVPTC subtypes (22 IEFVPTC, and 11 IFVPTC) were analyzed using the Image J image processing program. Tumour cells were compared for both nuclear morphometry and chromatin textural characteristics. Results: Nuclei from NIFTP and IFVPTC tumours differed in terms of chromatin textural features (grey intensity): mean (92.37 ± 21.01 vs 72.99 ± 14.73, p = 0.02), median (84.93 ± 21.17 vs 65.18 ± 17.08, p = 0.02), standard deviation (47.77 ± 9.55 vs 39.39 ± 7.18; p = 0.02), and coefficient of variation of standard deviation (19.96 ± 4.01 vs 24.75 ± 3.31; p = 0.003). No differences were found in relation to IEFVPTC. Conclusion: Computerized image analysis revealed differences in nuclear texture between NIFTP and IFVPTC, but not for IEFVPTC.

Hypoxia Induces Epithelial-Mesenchymal Transition in Follicular Thyroid Cancer: Involvement of Regulation of Twist by Hypoxia Inducible Factor-1alpha

PURPOSE: Although follicular thyroid cancer (FTC) has a relatively fair prognosis, distant metastasis sometimes results in poor prognosis and survival. There is little understanding of the mechanisms contributing to the aggressiveness potential of thyroid cancer. We showed that hypoxia inducible factor-1alpha (HIF-1alpha) induced aggressiveness in FTC cells and identified the underlying mechanism of the HIF-1alpha-induced invasive characteristics. MATERIALS AND METHODS: Cells were cultured under controlled hypoxic environments (1% O2) or normoxic conditions. The effect of hypoxia on HIF-1alpha, and epithelial-to-mesenchymal transition (EMT) related markers were evaluated by quantitative real-time PCR, Western blot analysis and immunocytochemistry. Invasion and wound healing assay were conducted to identify functional character of EMT. The involvement of HIF-1alpha and Twist in EMT were studied using gene overexpression or silencing. After orthotopic nude mouse model was established using the cells transfected with lentiviral shHIF-1alpha, tissue analysis was done. RESULTS: Hypoxia induces HIF-1alpha expression and EMT, including typical morphologic changes, cadherin shift, and increased vimentin expression. We showed that overexpression of HIF-1alpha via transfection resulted in the aforementioned changes without hypoxia, and repression of HIF-1alpha with RNA interference suppressed hypoxia-induced HIF-1alpha and EMT. Furthermore, we also observed that Twist expression was regulated by HIF-1alpha. These were confirmed in the orthotopic FTC model. CONCLUSION: Hypoxia induced HIF-1alpha, which in turn induced EMT, resulting in the increased capacity for invasion and migration of cells via regulation of the Twist signal pathway in FTC cells. These findings provide insight into a possible therapeutic strategy to prevent invasive and metastatic FTC.

Immunohistochemical analysis of thyroid follicular neoplasms and BRAF mutation correlation.

BACKGROUND: The accurate diagnosis of benign and malign thyroid tumors is very important for the clinical management of patients. The distinction of thyroid papillary carcinoma follicular variant and follicular adenoma can be difficult. AIM: To investigate the alternative methods like immunohistochemistry and exon 15 in the BRAF gene 1799 T/A mutation analyses for distinguishing thyroid tumors. MATERIALS AND METHODS: We applied immunohistochemical markers; CK19, HMWCK, Galectin‑3, HBME‑1 and Fibronectin and mutant allelespecific PCR amplification technique was used to determine 1799 T/A mutation within the BRAF gene. Formalin‑fixed parafin embedded tissues from 45 surgically total resected thyroids, included 26 thyroid papillary carcinoma follicular variant (FV‑TPC), 8 Follicular Adenoma (FA), 6 Minimal invasive follicular carcinoma (MIFC) and 5 Follicular Carcinoma (FC). STATISTICAL ANALYSES USED: Pearson Chi‑Square and Kruskal Wallis tests were performed. RESULTS: There was a positive correlation between FV‑TPC and HMWCK, CK 19, HBME1, Galectin 3, fibronectin (P < 0.05), but there was no correlation with FV‑TPC and BRAF gene mutation (P > 0.05). HBME‑1 and CK 19 stained strong and diffuse positive in FV‑TPCs but weak and focal in FAs. CONCLUSION: Our study suggests that morphologic features combined with immunohistochemical panel of HMWCK, CK19, HBME‑1, Galectin‑3 and fibronectin can help to distinguish benign and malign thyroid neoplasms and FV‑TPC from follicular adenomas. BRAF gene 1799 T/A mutation has been non‑specific but its detection can be a useful tool combined with immunohistochemistry for diagnosing FV‑TPC.

Comparative analysis of the prevalence of the glutathione S-transferase (GST) system in malignant and benign thyroid tumor cells

CONTEXT AND OBJECTIVE: When null, the mu and theta genes of the glutathione S-transferase system (GSTM1 and GSTT1, respectively) are related to malignant tumors affecting the lungs, colon, prostate, bladder and head and neck. In the thyroid, the appearance of cancer has been correlated with deletion of these genes. The aim of this study was to compare the frequencies of these genes in patients with benign and malignant tumors of the thyroid gland. DESIGN AND SETTINGS: This was a cross-sectional clinical trial carried out in the Head and Neck Surgery Division, Faculdade de Medicina da Santa Casa de São Paulo. METHODS: Samples of thyroid tissue were collected from 32 patients and divided into two groups: benign tumor (A) and malignant tumor (B). After DNA extraction, the genes were amplified using PCR. RESULTS: The B group presented four cases of positive genotyping for both genes, seven positive for GSTT1 and negative for GSTM1, two negative for GSTT1 and positive for GSTM1, and only one case of double negative. The A group showed 11 cases with positive genotyping for both genes and none with the double negative genotype. CONCLUSION: In this study, there was no relationship between the presence of the GSTT1 and GSTM1 genes and the benign and malignant thyroid tumors.

CONTEXTO E OBJETIVO: Os genes do sistema glutationa S-transferase mu e theta (GSTM1 e GSTT1, respectivamente), quando nulos, apresentam relação com tumores malignos de pulmão, cólon, próstata, bexiga e cabeça e pescoço, podendo nesses casos ser utilizados como marcadores tumorais. Na tireóide, o surgimento do câncer tem sido relacionado à deleção desses genes. Assim, o objetivo deste estudo foi comparar a freqüência dos genes GSTM1 e GSTT1 em pacientes com tumores benignos e malignos da glândula tireóide. TIPO DE ESTUDO E LOCAL: Estudo clínico transversal, realizado na Faculdade de Ciências Médicas da Santa Casa de São Paulo. MÉTODOS: Amostras de tecido tireoidiano foram coletados de 32 pacientes e divididas em dois: tumor benigno (A) e carcinoma (B). Após extração do DNA os genes foram amplificados em reação de polimerase em cadeia. RESULTADOS: O grupo B apresentou 4 casos de genótipo positivo para ambos os genes, 7 positivos para GSTT1 e negativos para GSTM1, 2 negativos para GSTT1 e positivos para GSTM1, e apenas 1 caso duplo negativo. Já o grupo A mostrou 11 casos com genótipo positivo para ambos os genes e nenhum com o genótipo duplo negativo. CONCLUSÃO: Não há relação entre a presença dos genes GSTT1 e GSTM1 com o carcinoma bem diferenciado e os tumores benignos da tireóide em nossos casos.

Carcinoma não medular familiar da tiróide / Familial nommedullary thyroid cancer

O carcinoma diferenciado da tiróide, papilífero ou folicular, origina-se da célula folicular tiroideana, sendo a neoplasia maligna mais freqüente desta glândula. Desde 1955 têm sido relatados casos de agrupamento familiar deste carcinoma, e atualmente estima-se que 4,2 por cento de todos os carcinomas diferenciados da tiróide tenham origem familiar. Esses casos costumam ser mais agressivos, incidem em idade mais precoce, são multifocais e apresentam maior taxa de recorrência. Parecem ser transmitidos por herança autossômica dominante com penetrância variável, mas os genes exatos responsáveis pela doença ainda não foram totalmente identificados. Os pacientes devem ser tratados com tiroidectomia total e freqüentemente também com esvaziamento linfonodal cervical, seguidos de ablação com iodo radioativo e terapia supressiva do TSH com levotiroxina. Alguns autores recomendam rastreamento de familiares de primeiro grau dos pacientes afetados através da ultrassonografia cervical, com objetivo de realizar diagnóstico precoce, possibilitando melhores resultados terapêuticos.

Nonmedullary thyroid carcinoma, originating from thyroid epithelial cells, is the most frequent thyroid malignant neoplasia. Since 1955, there has been increasing evidence that this cancer may have a familial predisposition. It is now established that around 4.2 percent of all nonmedullary thyroid carcinomas occurs on the background of familial predisposition. These cases are often more aggressive, due to early onset, multifocality and a higher percentual of recurrences. An autossomal dominant inheritance pattern appears likely in most families, although the exact genes responsible for this syndrome have not yet been identified. Patients affected by this cancer should be treated with total thyroidectomy routinely and, in most cases, lymph node dissection, followed by iodine ablation and TSH suppressive therapy with levothyroxine. Some authors also recommend that first-degree relatives of patients with nonmedullary thyroid cancer (especially women) should be submitted to neck ultrasound for thyroid cancer screening, aiming early diagnosis for better treatment results.

Nódulos com diagnóstico de padrão folicular: marcadores biológicos são o futuro? / Nodule diagnosed as follicular patterned lesion: are biomarkers the promise?

Com o uso da ultra-sonografia de alta resolução, a prevalência de nódulos tem aumentado e, conseqüentemente, o número de punção aspirativa por agulha fina (PAAF), que é o método de escolha para diagnóstico inicial. Um dos maiores dilemas clínicos para o citologista é o diagnóstico diferencial das lesões foliculares comumente agrupadas na classe padrão folicular. Neste artigo de revisão, discutiremos quais são as lesões que podem ser assim classificadas e os marcadores moleculares, identificados por nós ou por outros grupos, que são capazes de distinguir as lesões benignas das malignas.

There are an increasing number of thyroid nodules found by ultrasound and sampled by fine needle aspiration (FNA). A clinical problem is the accurate distinction between benign and malignant forms of follicular lesion. In this review we discuss the thyroid lesions that are common sources of diagnostic error, and grouped together as follicular patterned lesion, and the molecular markers identified by us and others, and that are able to distinguish the benign from the malignant ones.

Patogênese dos tumores diferenciados da tiróide (papilífero e folicular) / Pathogenesis of differentiated thyroid cancer (papillary and follicular)

Os carcinomas diferenciados da tiróide, o papilífero (PTC) e o folicular (FTC) são as neoplasias endócrinas mais comuns. Descobertas recentes esclareceram diversos aspectos de sua patogênese, analisados nesta revisão. No PTC, uma única mutação no gene BRAF (o gene da Raf quinase tipo B) (V600E) é responsável pela doença em 40-50% dos pacientes, especialmente os mais velhos e os que apresentam subtipos histológicos mais agressivos. Tendo em vista esses fatores prognósticos da mutação BRAF, o uso de sua pesquisa no material proveniente do exame citológico de tiróide pode ser útil para fins de diagnóstico e conduta. A outra causa freqüente de PTC são os rearranjos RET/PTC, decorrentes da quebra e fusão do domínio TK intra-celular de RET com fragmentos 5’ de diversos genes, resultando num gene quimérico que produz uma proteína que apresenta atividade constitutiva de uma tirosina quinase de RET, presentes em 20-30% dos pacientes, especialmente os mais jovens ou que receberam radiação. Já a patogênese do FTC é menos compreendida. Descreve-se a participação do gene decorrente da fusão entre PAX8 e PPARg (peroxisome proliferator-activated receptor g) em 30-50% dos pacientes com este tumor; entretanto, esta fusão pode ocorrer também em adenomas foliculares. Desta forma, ainda não há evidência completa de que PAX8-PPARg seja a causa do FTC. Outro achado no FTC são as mutações no gene RAS; quando ocorrem mutações do RAS não acontece o rearranjo PAX8-PPARg. Outra possível causa de FTC é a perda ou expressão exagerada de uma série de genes, alguns demonstrados por técnicas de expressão diferencial de genes, como TRg, PTEN, PKAR1A, DDIT3, ARG2, ITM1 e C1orf24.