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In tumor biology, hypoxia triggers signaling pathways that induce transcription of genes related to angiogenesis, metastasis, glucose metabolism and apoptosis. We investigated the expression of hypoxia related proteins, galectin-3 (Gal-3) and hypoxia-inducible factor-1α (HIF-1α), in conventional (CA) and unicystic ameloblastomas (UA). We applied immunohistochemistry for Gal-3 and HIF-1α to 72 cases of ameloblastoma: 59 cases of CA and 13 cases of unicystic UA. Immunoexpression was evaluated semiquantitatively. Gal-3 expression was observed in 40% of the cases: 23/59 CA and 6/13 UA. HIF-1α immunostaining was observed in 55% of cases: 36/59 CA and 4/13 UA. 19 CA and 2 UA were positive for both markers. Immunostaining was evident in the center of the tumor islands, which exhibited squamous metaplasia or cystic degeneration. The expression of Gal-3 and HIF-1α in ameloblastomas could be interpreted as a response to hypoxic stress. Co-expression of both proteins in CA may suggest a potential interaction that participates in the biological behavior of this ameloblastoma variant.

Resumen: Con el fin de tener una mayor comprensión sobre el comportamiento biológico del mixoma odontogénico (MO), se realizó inmunohistoquímica en 31 muestras, utilizando marcadores relacionados con mecanismos de progresión tumoral (adhesión, angiogénesis, apoptosis, inflamación y proliferación celular). Epitelio odontogénico fue detectado en cuatro muestras mediante CK19 y CD138, este último, mostró expresión baja en matriz extracelular (MEC) y alta en las células tumorales. La microdensidad vascular (MDV) media fue de 7.51 y 5.35 vasos marcados con CD34 y VEGF-A respectivamente. Una alta expresión de Orosomucoide-1 y Mast Cell Tryptase se observó células tumorales y en MEC. El MO mostró negatividad para Calretinina. Este perfil inmunohistoquímico, la baja expresión para Ki-67, Bcl-2 y p53, y la relativamente baja MDV, sugieren que la actividad proliferativa, anti-apoptótica o angiogénica no representan los principales mecanismos de crecimiento del MO, los cuales podrían estar asociados a eventos como inmunomodulación y degradación de la MEC. Resumo: Para melhor compreensão do comportamento biológico do mixoma odontogênico (MO), imuno-histoquímica foi realizada em 31 amostras, utilizando marcadores relacionados aos mecanismos de progressão tumoral (adesão, angiogênese, apoptose, inflamação e proliferação celular). Epitélio odontogênico foi detectado em quatro amostras por CK19 e CD138, o último mostrou baixa expressão na matriz extracelular (MEC) e alta em células tumorais. A microdensidade vascular (MDV) média foi de 7.51 e 5.35 vasos marcados com CD34 e VEGF-A, respectivamente. Uma alta expressão de Orosomucoide-1 e Mast Cell Tryptase foi observada nas células tumorais e na MEC. O MO mostrou negatividade para Calretinina. O perfil imuno-histoquímico mencionado acima, a baixa expressão de Ki-67, Bcl-2 e p53 e a relativamente baixa MDV, sugerem que a atividade proliferativa, anti-apoptótica ou angiogênica não representam os principais mecanismos de crescimento do MO, os quais poderiam estar associados com eventos como imunomodulação e degradação da MEC. Abstract: In order to elucidate better the biological behavior of the odontogenic myxoma (OM), immunohistochemistry was performed in 31 samples, using markers related to mechanisms of tumor progression (adhesion, angiogenesis, apoptosis, inflammation and cell proliferation). Odontogenic epithelium was detected in four samples with CK19 and CD138, the latter had a low-expression in extracellular matrix (ECM) and a high-expression in tumor cells. The mean microvascular density (MVD) assessed with CD34 and VEGF-A, was 7.51 and 5.35 blood vessels respectively. A high-expression of Orosomucoid-1 and Mast Cell Tryptase was observed in tumor cells and ECM, while Calretinin was completely negative. The previously mentioned immunohistochemical profile, as well as the low expression of Ki-67, Bcl-2 and p53 and the relatively low MVD, suggests that the proliferative, anti-apoptotic and angiogenic activities do not represent the main growing mechanisms of OM, which could be associated to other events, such as immunomodulation and ECM degradation.

Objective To determine the immunoexpression of CD138, CK19 CD34, vascular endothelial growth factor (VEGF), BCL-2, p53, KI-67, mast cell tryptase, calretinina, and orosomucoid 1 in odontogenic myxomas (OMs). Study Design Analytical and retrospective study was conducted. Immunohistochemistry was performed for 30 cases of OM. Results Four CK19 and CD138 samples were positive, confirming the presence of odontogenic epithelium; also, CD138 was found in the extracellular matrix (moderated immunoexpression), and tumoral cells (high immunoexpression). Microvascular density (MVD) was measured with CD34 and VEGF expression, being 7.51 and 5.35 blood vessels, respectively. Orosomucoid 1 and mast cell tryptase showed a high immunoexpression in tumoral cells. Calretinin was negative in all the samples. KI67, BCL2 and p53 showed a low expression. Conclusions The high immunopositivity found in orosomucoide 1, VEGF, and mast cell tryptase suggests a proangiogenic modulator among these proteins. The presence of CD138 in tumor cells and extracellular matrix suggests a relationship between this protein and extracellular components of OM, even though its role on this neoplastic process should be clarified.

Resumen: El objetivo de este estudio fue conocer la expresión de MCM4-5-6 en gérmenes dentarios humanos en estado de campana. Materiales y Métodos Se obtuvieron preparados histológicos de 4 maxilares fetales incluidos en parafina en el archivo de bloques de la cátedra de Histología de la Facultad de Odontología, UdelaR. Se procedió al corte de los mismos en secciones para técnica de rutina (HE) y de IHQ para MCM 4, 5 y 6. Resultados: Las diferentes regiones del órgano del esmalte mostraron 100 % de positividad en el estrato intermedio, una variación de 100 % a 0 % en el epitelio interno del órgano del esmalte, desde el sector cervical al sector incisal del mismo, y0% tanto en el retículo estrellado como en el epitelio externo del órgano del esmalte. Conclusiones: Los resultados obtenidos permitieron evidenciar y confirmar la acción proliferativa de las diferentes zonas del órgano del esmalte. Abstract The aim of this study was to determine the expression of MCM4-5-6 in human tooth germs in the bell stage. Materials and methods: Histological samples were collected from four fetal maxillae placed in paraffin at the block archive of the Histology Department of the School of Dentistry, UdelaR. Sections were made for HE routine technique and for immunohistochemistry technique for MCM4-5-6. Results: Different regions of the enamel organ showed 100% positivity in the intermediate layer, a variation from 100% to 0% in the inner epithelium from the cervical loop to the incisal area, and 0% in the stellar reticulum as well as the outer epithelium. Conclusions: The results show and confirm the proliferative action of the different areas of the enamel organ.

José Verocay (Paysandú 1876 - Eichwald/Dubí, Bohemia 1927) was a Uruguayan anatomopathologist, recognized worldwide as "Prague's pathologist" (Fig. 1). In 1910, he described, for the first time, the morphological structure later called Verocay's bodies, which are used for diagnosing schwannoma. He spent the end of the XIXth century and the beginning of XXth century in Charles-Ferdinand University in Prague. During the last years of his life, he tried unsuccessfully to reintegrate himself into the Uruguayan academic community. In 1927, he passed away in Eichwald, Teplitz district, Bohemia. Keywords: Prague's pathologist - Veroca y - Verocay's bodies.

Introduction. Solid/conventional ameloblastoma (AM) and unicystic ameloblastoma (UAM) are the most frequent benign epithelial odontogenic tumors located in the maxillary region, and their treatment usually consists of extensive surgical resection. Therefore, it is relevant to study molecular markers to better understand the biological behavior of these tumors. The aim of this study was to describe and compare the expression of proteins related to cellular proliferation: Ki-67 and MCM4-6 complex. Materials and Methods. An immunohistochemistry technique was performed, with antibodies against Ki-67, MCM4, MCM5, and MCM6, in 10 AM and 10 UAM tumors. The results were quantified using label index and analyzed statistically. Results. AM and UAM had greater expression of MCM6, followed by MCM5, MCM4, and Ki-67 ( P < .05). Immunoexpression of Ki-67 and MCM5 was exclusively nuclear, whereas the expression of MCM4 and MCM6 was nuclear and cytoplasmic. Conclusion. The results suggest that MCM5 is a trustable cell proliferation marker with higher sensitivity compared with Ki-67 and may be useful to predict the biological behavior of AM and UAM. Despite this, further studies are necessary, including a correlation with clinical parameters to confirm these findings.