Rapid methods to create a positive control and identify the PAX8/PPARγ rearrangement in FNA thyroid samples by molecular biology.

Thyroid cancer is the most common malignancy of the endocrine system and includes well-differentiated forms, namely papillary and follicular carcinomas, and the poorly differentiated and undifferentiated forms that result from the transformation of thyroid follicular cells (anaplastic carcinomas). Notably, 5-10% of all thyroid cancers are medullary thyroid cancers that arise from parafollicular cells also known as C cells. The most common genetic mutations in papillary and follicular thyroid cancers are point mutations of the BRAF or RAS genes, while the most common chromosomal alterations are RET/PTC and PAX8/PPARγ rearrangements. The most frequent initial manifestation of thyroid cancer is the appearance of a nodule most of which are benign; indeed, less than 5% are malignant. However, some cases are misdiagnosed, and many patients undergo unnecessary surgery. Therefore, an accurate pre-surgery evaluation is crucial. The most reliable diagnostic test for thyroid nodules is fine needle aspiration (FNA) cytology, which accurately distinguishes between a benign and malignant lesion in most cases. However, cytological discrimination between malignant and benign follicular cancer is often difficult because of poor quality samples. Here we describe rapid methods to create a positive control and identify the PAX8/PPARγ rearrangement in FNA thyroid samples by molecular biology.

PATZ1 acts as a tumor suppressor in thyroid cancer via targeting p53-dependent genes involved in EMT and cell migration.

PATZ1, a POZ-Zinc finger protein, is emerging as an important regulator of development and cancer, but its cancer-related function as oncogene or tumor-suppressor is still debated. Here, we investigated its possible role in thyroid carcinogenesis. We demonstrated PATZ1 is down-regulated in thyroid carcinomas compared to normal thyroid tissues, with an inverse correlation to the degree of cell differentiation. In fact, PATZ1 expression was significantly further down-regulated in poorly differentiated and anaplastic thyroid cancers compared to the papillary histotype, and it resulted increasingly delocalized from the nucleus to the cytoplasm proceeding from differentiated to undifferentiated thyroid carcinomas. Restoration of PATZ1 expression in three thyroid cancer-derived cell lines, all characterized by fully dedifferentiated cells, significantly inhibited their malignant behaviors, including in vitro proliferation, anchorage-independent growth, migration and invasion, as well as in vivo tumor growth. Consistent with recent studies showing a role for PATZ1 in the p53 pathway, we showed that ectopic expression of PATZ1 in thyroid cancer cells activates p53-dependent pathways opposing epithelial-mesenchymal transition and cell migration to prevent invasiveness. These results provide insights into a potential tumor-suppressor role of PATZ1 in thyroid cancer progression, and thus may have potential clinical relevance for the prognosis and therapy of thyroid cancer.

miR-142-3p down-regulation contributes to thyroid follicular tumorigenesis by targeting ASH1L and MLL1.

CONTEXT: A previous micro-RNA expression profile of thyroid follicular adenomas identified miR-142 precursor among the miRNAs downregulated in the neoplastic tissues compared to normal thyroid gland. OBJECTIVE: The aim of this work has been to assess the expression of miR-142-3p in a large panel of follicular thyroid adenomas and carcinomas and evaluate its effect on thyroid cell proliferation and target expression. DESIGN: The expression of miR-142-3p was analyzed by qRT-PCR in thyroid follicular adenomas and carcinomas, compared to normal thyroids. MiR-142-3p expression was restored in WRO cells and the effects on cell proliferation and target expression were evaluated. RESULTS: Here we show that miR-142-3p is downregulated in FTAs, FTCs, and FVPTCs. MiR-142-3p was demonstrated to reduce the proliferation rate of WRO and FTC133 cells, supporting its tumor suppressor role in thyroid cancerogenesis. Moreover, this microRNA was able to downregulate the expression of ASH1L and MLL1, by direct and indirect mechanisms, respectively. Consistently, an inverse correlation between miR-142-3p expression and ASH1L and MLL1 proteins was found in thyroid follicular adenomas and carcinomas. ASH1L and MLL1, which belong to the Trithorax group (TrxG) proteins and are major regulators of Homeobox gene expression, maintain active target gene transcription by histone 3 lysine 4 methylation. Interestingly, we found that FTCs and FTC cell lines express tumor specific, shorter forms of the two proteins. The capability of miR-142-3p to modulate the levels of these tumor-associated forms and to reactivate thyroid-specific Hox gene expression, likely contributes to its tumor suppressive function. CONCLUSIONS: These data demonstrate that miR-142-3p downregulation has a role in thyroid tumorigenesis, by regulating ASH1L and MLL1.

High HMGA2 expression and high body mass index negatively affect the prognosis of patients with ovarian cancer.

HMGA2 is a small, non-histone, chromatin-associated protein with a key role in tumorigenesis and adipogenesis. Indeed, HMGA2 overexpression has been frequently detected in several malignant neoplasms and inhibition of its expression prevents thyroid cell transformation. Moreover, HMGA2 null mice show a pigmy phenotype with a great reduction in fat tissue. To investigate whether HMGA2 expression correlates with clinico-pathological parameters and patient outcome, immunohistochemical analysis of HMGA2 expression was performed in ovarian cancer specimens from 117 patients. HMGA2 overexpression was found in 39% of the cases and, interestingly, positively correlated with the body mass index (BMI). Moreover, high BMI (≥ 25 kg/m(2) ) and high HMGA2 expression/BMI combined evaluation predicted shorter disease-free survival. High BMI (≥ 25 kg/m(2) ), high expression of HMGA2 and high HMGA2 expression/BMI combined evaluation predicted shorter overall survival. In multivariate analysis, the concomitant high expression of HMGA2 and high BMI (≥ 25 kg/m(2) ) was an independent prognostic factor. Finally, the BMI (≥ 25 kg/m(2) ) negatively correlated with the patient response to chemotherapy (P=0.039). Therefore, the data reported herein suggest that the combined evaluation of HMGA2 expression and obesity assessed through BMI can be considered a marker of poor prognosis in patients affected by ovarian carcinoma.

CBX7 Expression in Oncocytic Thyroid Neoplastic Lesions (Hürthle Cell Adenomas and Carcinomas).

BACKGROUND: Previous analysis of CBX7 expression in a large number of thyroid adenoma and carcinoma samples revealed a progressive reduction of CBX7 levels that was well related with the malignant grade of thyroid neoplasias. Hürthle cell tumors are unusual thyroid neoplasms characterized by the presence of particular cells called oncocytes. OBJECTIVES: In order to develop new tools for a more accurate diagnosis of Hürthle cell tumors of the thyroid, we evaluated CBX7 protein levels to verify the possible presence of an expression signature. METHODS: CBX7 expression was evaluated by immunohistochemistry in a panel of thyroid tissue sections including normal thyroids, goiters, follicular adenomas and oncocytic lesions. RESULTS: CBX7 expression was low or null in 68% of Hürthle adenomas, whereas it was comparable to normal thyroid tissue in Hürthle hyperplasias and follicular adenomas. CONCLUSIONS: Reduced expression of CBX7 suggests a more aggressive identity of Hürthle adenomas with respect to non-Hürthle ones.