Detection of DNA methylation of HYAL2 gene for differentiating malignant from benign thyroid tumors / 南方医科大学学报

OBJECTIVE@#To assess the value of DNA methylation level of HYAL2 gene as a molecular marker for differential diagnosis of malignant and benign thyroid tumors.@*METHODS@#DNA methylation of HYAL2 gene in tissue specimens of 190 patients with papillary thyroid cancer (PTC) and 190 age- and gender-matched patients with benign thyroid tumors was examined by mass spectrometry, and the protein expression of HYAL2 was detected immunohistochemically for another 55 pairs of patients. Logistic regression analysis was performed to calculate the odds ratio (OR) and evaluate the correlation of per 10% reduction in DNA methylation with PTC. Receiver operating characteristic (ROC) curve analysis was performed and the area under curve (AUC) was calculated to assess the predictive value of alterations in HYAL2 methylation.@*RESULTS@#Hypomethylation of HYAL2_CpG_3 was significantly correlated with early-stage PTC (OR=1.51, P=0.001), even in stage I cancer (OR=1.42, P=0.007). Age-stratified analysis revealed a significantly stronger correlation between increased HYAL2_CpG_ 3 methylation and early-stage PTC in patients below 50 years than in those older than 50 years (OR: 1.89 vs 1.37, P < 0.05); ROC analysis also showed a larger AUC of 0.787 in younger patients. The results of immunohistochemistry showed that patients with PTC had significantly higher protein expressions of HYAL2 than patients with benign tumors.@*CONCLUSION@#The alterations of DNA methylation level of HYAL2 gene is significantly correlated with early-stage PTC, suggesting the value of DNA methylation level as a potential biomarker for differentiation of malignant from benign thyroid tumors.

Molecular genetic analysis of primary renal epithelial tumours with granular oncocytic cytoplasms / Análisis genético molecular de tumores epiteliales renales primarios con citoplasma oncocítico granular

SUMMARY: The group of primary renal tumours with granular-oncocytic cytoplasm is a very heterogeneous group, in its histological origin and biological behavior resulting in many diagnostic problems. In this study 57 renal epithelial tumours with granular oncocytic cells were analyzed using fluorescence in situ hybridisation (FISH), array comparative genomic hybridisation (aCGH) and polymerase chain reaction (PCR). The results of analysis in renal oncocytoma (RO) did not indicate the presence of the gene mutations or chromosomal abnormalities. Sporadic renal hybrid oncocytic/chromophobe tumours (HOCT) had multiple numerical aberrations of chromosomes 1, 2, 6, 9, 10, 13, 17, 20, 21 and 22. This type of tumour had no mutations in the VHL, c-kit, PDGFRA, and FLCN genes. Oncocytic papillary renal cell carcinoma (O-PRCC) had numerical abnormalities of chromosomes 7 and 17 and the loss of the Y chromosome. Cytogenetic analysis of 20 pigmented microcystic chromophobe renal cell carcinomas (PMChRCC) showed monosomy as the most frequent aberration in all analyzed chromosomes 1, 2, 5, 10, 13, 17 and 21. One case of chromophobe renal cell carcinoma (ChRCC) with hyaline globules had a mutation in the distal part of exon 3 of the VHL gene. Absence of genetic disorders in usual RO is common result, but we have established absence of genetic disorders even in rare variants. Variety of genetic alterations detected in sporadic renal HOCT proves it to be a separate entity, not a variant of ChRCC, while PMChRCC is an uncommon variant of ChRCC. O-PRCC is a subtype of papillary renal cell carcinoma.

RESUMEN: El grupo de tumores renales primarios con citoplasma granular-oncocítico es un grupo muy heterogéneo, en su origen histológico y comportamiento biológico, resultando en problemas de diagnóstico. En el estudio se analizaron 57 tumores epiteliales renales con citoplasma oncocítico granular mediante hibridación fluorescente in situ (FISH), hibridación genómica comparativa de matriz (aCGH) y reacción en cadena de la polimerasa (PCR). Los resultados del análisis en oncocitoma renal (RO) no indicaron la presencia de mutaciones genéticas ni anomalías cromosómicas. Los tumores oncocíticos / cromófobos híbridos renales esporádicos (HOCT) tenían múltiples aberraciones numéricas de los cromosomas 1, 2, 6, 9, 10, 13, 17, 20, 21 y 22. No se observaron mutaciones en este tipo de tumor en el VHL, c-kit, PDGFRA y genes FLCN. El carcinoma de células renales papilar oncocítico (O-PRCC) tenía anomalías numéricas de los cromosomas 7 y 17 y la pérdida del cromosoma Y. El análisis citogenético de 20 carcinomas de células renales cromófobos microquísticos pigmentados (PMChRCC) mostró que la monosomía era la aberración más frecuente en todos los cromosomas analizados 1, 2, 5, 10, 13, 17 y 21. Un caso de carcinoma de células renales cromófobo (CCRc) hialino tenía una mutación en la parte distal del exón 3 del gen VHL. La ausencia de trastornos genéticos en la OI habitual es un resultado común, pero hemos establecido la ausencia de trastornos genéticos incluso en variantes raras. Varias alteraciones genéticas detectadas en esporádica HOCT renal demuestran que es una entidad separada, no una variante de ChRCC, mientras que PMChRCC es una variante poco común de ChRCC. O-PRCC es un subtipo de carcinoma papilar de células renales.

20 years of RET/PTC in thyroid cancer: clinico-pathological correlations

The RET/PTC oncogene has been isolated almost twenty years ago. During these years, the research has given a final answer to several questions. In fact, it has been demonstrated that: a) RET/PTC is an early event in the process of thyroid carcinogenesis and has a critical role in the generation of the papillary carcinoma; b) RET/PTC activation is essentially restricted to the papillary histotype and to the Hürthle thyroid tumors; c) its incidence increases after exposure to radiations. However, some questions have not found a final answer yet: a) which is the real frequency of RET/PTC activation? Likely it is around 20 percent, but this point is still questionable; b) which other gene modifications are required to lead a thyroid cell carrying a RET/PTC oncogene to the malignant phenotype?, and c) is there any correlation between RET/PTC activation and clinical parameters? We hope that these questions will have a clear answer in the near future.

O oncogene RET/PTC foi isolado há quase 20 anos atrás. Durante esses anos de pesquisa várias questões foram solucionadas. Na verdade, já foi demonstrado que: a) o RET/PTC é um evento precoce no processo da carcinogênese da tiróide e tem um papel crítico na geração do carcinoma papilífero; b) a ativação do RET/PTC está restrita essencialmente ao histotipo papilar e aos tumores de Hürthle; c) sua incidência aumenta após a exposição à radiação. Entretanto, algumas questões permanecem ainda sem uma resposta final: a) qual é a real freqüência de ativação do RET/PTC? Provavelmente em torno de 20 por cento, mas este número ainda é questionável; b) quais outras modificações gênicas são necessárias para transformar uma célula tiroidiana que possui oncogene RET/PTC no fenotipo maligno?; e c) existe alguma correlação entre a ativação do RET/PTC e parametros clínicos? Esperamos que essas questões sejam solucionadas em futuro próximo.

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.