Marcadores biológicos de tumores tiroidianos

Expression of CK-19, galectin-3 and HBME-1 in the differentiation of thyroid lesions: systematic review and diagnostic meta-analysis

Background

To distinguish between malignant and benign lesions of the thyroid gland histological demonstration is often required since the fine-needle aspiration biopsy method applied pre-operatively has some limitations. In an attempt to improve diagnostic accuracy, markers using immunocytochemistry and immunohistochemistry techniques have been studied, mainly cytokeratin-19 (CK-19), galectin-3 (Gal-3) and Hector Battifora mesothelial-1 (HBME-1). However, current results remain controversial. The aim of the present article was to establish the diagnostic accuracy of CK-19, Gal-3 and HBME-1 markers, as well as their associations, in the differentiation of malignant and benign thyroid lesions.

Methods

A systematic review of published articles on MEDLINE and The Cochrane Library was performed. After establishing inclusion and exclusion criteria, 66 articles were selected. The technique of meta-analysis of diagnostic accuracy was employed and global values of sensitivity, specificity, area under the summary ROC curve, and diagnostic odds ratio (dOR) were calculated.

Results

For the immunohistochemistry technique, the positivity of CK-19 for the diagnosis of malignant thyroid lesions demonstrated global sensitivity of 81% and specificity of 73%; for Gal-3, sensitivity of 82% and specificity of 81%; and for HBME-1, sensitivity of 77% and specificity of 83%. The association of the three markers determined sensitivity of 85%, specificity of 97%, and diagnostic odds ratio of 95.1. Similar results were also found for the immunocytochemistry assay.

Conclusion

This meta-analysis demonstrated that the three immunomarkers studied are accurate in pre- and postoperative diagnosis of benign and malignant thyroid lesions. Nevertheless, the search for other molecular markers must continue in order to enhance this diagnostic accuracy since the results found still show a persistency of false-negative and false-positive tests.

Virtual slides

Http://www.diagnosticpathology.diagnomx.eu/vs/3436263067345159

Cytophotometric expression of Caspase-3 in papillary thyroid carcinoma in nodular goiter colloid

OBJECTIVE

To describe quantitative cytophotometric expression of the marker caspase-3 in colloid goiter and in papillary carcinoma of the thyroid, comparing the immunoexpression between them.

METHODS

An immunohistochemistry study has been made on the protein caspase-3 in 17 of paraffin blocks of papillary carcinoma of the thyroid and 20 cases of colloid goiter, using SAMBA 4000 ® (System of Microscopic Analysis of Automatic Search), aiming analysis of the two variables: marker index and optical density.

RESULTS

Statistic analysis indicated a significant difference for marker index between colloid goiter and papillary carcinoma, being this difference larger in the carcinoma. Significant difference in optical density hasn't been found. For colloid goiter, the estimated correlation coefficient between the marker index and optical density was 0,72, indicating the rejection of the null hypothesis (p <0,001), affirming that positive and significant association exists between them. For the papillary carcinoma of the thyroid, the same correlation was 0,34 and so, it is not possible to affirm that there's an association between them.

CONCLUSION

For colloid goiter there is a positive and significant association between the two variables - marker index and optical density -, while for the papillary carcinoma, this is not proved. The quantitative analysis for caspase-3 demonstrates that apoptosis is larger in the papillary carcinoma of the thyroid than in colloid goiter.

Thyroid tissue analysis through Raman spectroscopy

The diagnosis of thyroid pathologies is usually made by cytologic analysis of the fine needle aspiration (FNA) material. However, this procedure has a low sensitivity at times, presenting a variation of 2-37%. The application of optical spectroscopy in the characterization of alterations could result in the development of a minimally invasive and non-destructive method for the diagnosis of thyroid diseases. Thus, the objective of this work was to study the biochemical alterations of tissues and hormones (T3 and T4) of the thyroid gland by means of molecular vibrations probed by FT-Raman spectroscopy. Through the discriminative linear analysis of the Raman spectra of the tissue, it was possible to establish (in percentages) the correct classification index among the groups: goitre adjacent tissue, goitre nodular region, follicular adenoma, follicular carcinoma and papillary carcinoma. As a result of the comparison between the groups goitre adjacent tissue versus goitre nodular region, an index of 58.3% of correct classification was obtained; this percentage was considered low, and it was not possible to distinguish the Raman spectra of these groups. Between goitre (nodular region and adjacent tissue) versus papillary carcinoma, the index of correct classification was 64.9%, which was considered good. A relevant result was obtained in the analysis of the benign tissues (goitre and follicular adenoma) versus malignant tissues (papillary and follicular carcinomas), for which the index was 72.5% and considered good. It was also possible, by means of visual observation, to find similar vibrational modes in the hormones and pathologic tissues. In conclusion, some biochemical alterations, represented by the FT-Raman spectra, were identified that could possibly be used to classify histologic groups of the thyroid. However, more studies are necessary due to the difficulty in setting a standard for pathologic groups.

Expressão citofotométrica do fator de proliferação celular ki-67 no bócio colóide e no carcinoma papilífero da tireóide

OBJETIVO: Comparar a expressão citofotométrica quantitativa do fator de proliferação celular Ki-67 no bócio colóide com o do carcinoma papilífero da tireóide. MÉTODOS: Foram estudadas a expressão da proteína Ki-67, em 12 casos de bócio colóide da tireóide e 20 casos de carcinoma papilífero da tireóide. Os núcleos celulares imunomarcados foram quantificados através do software SAMBA 4000 ® e do software IMMUNO®, analisando o índice de marcagem e densidade óptica. Foi estimado o coeficiente de correlação de Spearmane e o teste não-paramétrico de Mann-Whitney. RESULTADOS: Foi rejeitada a hipótese nula para o índice de marcagem. confirmando que existe diferença significativa entre o bócio colóide e o carcinoma papilífero da tireóide, quanto ao índice de marcagem do Ki-67, que são maiores nos carcinomas papilíferos da tireóide. Não foi encontrada diferença quanto à densidade óptica. Quanto ao bócio colóide, o coeficiente de correlação estimado entre o índice de marcagem e a densidade óptica do Ki-67 foi igual a 0,78. No bócio colóide, houve associação positiva e significativa entre o índice de marcagem e a densidade ótica do Ki-67. Para o carcinoma papilífero da tireóide o coeficiente de correlação estimado entre o índice de marcagem e a densidade ótica do Ki-67 foi igual a 0,18. Não houve no carcinoma papilífero de tireóide, associação entre o índice de marcagem e a densidade ótica do Ki-67. CONCLUSÃO: A expressão citofotométrica do Ki67 no bócio colóide teve índice médio de marcação de 13,92% e densidade óptica média de 36,43; a expressão citofotométrica do Ki-67 no carcinoma papilífero teve índice médio de marcação de 38,29% e densidade óptica média de 48,07%; há maior proliferação celular no carcinoma papilífero em comparação com o bócio colóide na expressão do Ki-67.

Thyroid fine-needle aspiration samples inadequate for reverse transcriptase-polymerase chain reaction analysis

BACKGROUND

Analysis of different tumor markers by reverse transcriptase-polymerase chain reaction (RT-PCR) in fine-needle aspiration samples of thyroid nodules has been studied with the objective of improving the accuracy of the preoperative diagnosis of thyroid lesions. The aim of the current study was to investigate thyroid fine-needle aspiration samples inadequate for RT-PCR analysis and to determine whether there is a correlation between their proportion and the method of sampling used or the greatest dimension of the nodules.

METHODS

A total of 350 fine-needle aspiration samples from patients with thyroid nodules were analyzed. After the aspirate was smeared for conventional cytology, the leftover material in the needle was used for RT-PCR analysis in 1 group of 175 patients. In another group of 175 patients, a separate puncture was performed to obtain material for RT-PCR analysis only. Samples were considered adequate for RT-PCR analysis if the expression of both glyceraldehyde-3-phosphate dehydrogenase and thyroglobulin was found by RT-PCR.

RESULTS

In total, 61 (17.4%) samples inadequate for RT-PCR were detected. All 12 samples that were inadequate for cytologic diagnosis were also found to be inadequate for RT-PCR analysis. The proportion of inadequate samples for RT-PCR was found to be significantly higher in samples taken from leftover material in the needle (21.7%) then in samples from a separate puncture (13.1%) (P = .049). No statistically significant correlation between the adequacy of samples for RT-PCR and the largest dimension of the nodule was found.

CONCLUSIONS

The proportion of samples inadequate for RT-PCR was found to be higher in samples taken from leftover material in the needle than in samples obtained from a separate puncture.

Papillary thyroid carcinoma in a 9-year-old girl with ataxia-telangiectasia

A 9-year-old female with ataxia-telangiectasia (AT) presenting with papillary thyroid carcinoma and lymph nodes involvement is reported. We discuss this novel association, the general risk of neoplasic complications in these patients, the natural history of thyroid carcinoma in the pediatric population and the potential link between thyroid carcinogenesis and ataxia-telangiectasia mutated gene (ATM) mutation. We also expose our therapeutic attitude, according to both clinical status and particular genetic background of our patient.

TGFbeta, activina e sinalização SMAD em câncer de tiróide

TGFbeta e activina são membros da superfamília TGFbeta e desempenham um amplo papel no desenvolvimento, proliferação e apoptose. Estes fatores de crescimento exercem seus efeitos biológicos ligando-se a receptores de membrana do tipo I e do tipo II que transduzem a sinalização até o núcleo através da fosforilação das proteínas R-SMADs (SMAD 2/3) e co-SMADs (SMAD4). O controle apropriado da via de TGFbeta/activina ainda depende da regulação negativa exercida pelo SMAD inibitório (SMAD7) e pelas enzimas E3 de ubiquitinação (Smurfs). Fisiologicamente, TGFbeta e activina atuam como potentes inibidores da proliferação na célula folicular tiroidiana. Desta forma, alterações de receptores e componentes da via de sinalização SMAD estão associadas a diferentes tipos de tumores. Desde que TGFbeta e activina geram sua sinalização intracelular utilizando os mesmos componentes da via SMAD, o desequilíbrio desta via prejudica dois processos anti-mitogênicos da célula. Nesta revisão, enfocamos aspectos que indicam o mecanismo de resistência ao efeito inibitório de TGFbeta e activina ocasionado pelo desequilíbrio da via de sinalização SMAD nas neoplasias da tiróide.

Pathogenesis of differentiated thyroid cancer (papillary and follicular)

Differentiated thyroid cancers (papillary - PTC and follicular - FTC) are the most common endocrine malignancies. The recent progresses in the understanding of PTC and FTC pathogenesis are summarized in this review. In PTC, a single mutation of BRAF (the gene for the B-type Raf kinase) (V600E) is responsible for the disease in 40-50% of patients, especially in older people and is associated with a poorer clinicopathological outcome. Due to these characteristics, its use as a specific diagnostic and prognostic marker for PTC in cytological specimens is being implemented. Another important cause of PTC is rearrangements of the RET tyrosine kinase receptor (RET/PTC), which represent a recombination of the promoter and N-terminal domain of a partner gene with the C-terminal region of the RET gene, resulting in a chimeric gene with a protein product containing a constitutively activated RET tyrosine kinase, responsible for 20-30% patients, specially the younger or after radiation. The pathogenesis of FTC is less understood. A chromosomal translocation between the transcription factor PAX8 and the peroxisome proliferator-activated receptorgamma (PPARgamma) occurs in 30-50% of patients; however, the presence of PAX8-PPARgamma is also demonstrated in follicular adenomas. Therefore, there is no complete evidence that PAX8-PPARgamma is the cause of FTC. Another finding in FTC is mutations on the RAS gene, which excludes PAX8-PPARgamma rearrangements. Several genes, as TRgamma, PTEN, PKAR1A, DDIT3, ARG2, ITM1 and C1orf24 - some discovered by techniques of differential gene expression -, have been recently implicated in the pathogenesis of FTC.