Deregulation of DNMT1, DNMT3B and miR-29s in Burkitt lymphoma suggests novel contribution for disease pathogenesis.

Methylation of CpG islands in promoter gene regions is frequently observed in lymphomas. DNA methylation is established by DNA methyltransferases (DNMTs). DNMT1 maintains methylation patterns, while DNMT3A and DNMT3B are critical for de novo DNA methylation. Little is known about the expression of DNMTs in lymphomas. DNMT3A and 3B genes can be regulated post-transcriptionally by miR-29 family. Here, we demonstrated for the first time the overexpression of DNMT1 and DNMT3B in Burkitt lymphoma (BL) tumor samples (69% and 86%, respectively). Specifically, the treatment of two BL cell lines with the DNMT inhibitor 5-aza-dC decreased DNMT1 and DNMT3B protein levels and inhibited cell growth. Additionally, miR-29a, miR-29b and miR-29c levels were significantly decreased in the BL tumor samples. Besides, the ectopic expression of miR-29a, miR-29b and miR-29c reduced the DNMT3B expression and miR-29a and miR-29b lead to increase of p16(INK4a) mRNA expression. Altogether, our data suggest that deregulation of DNMT1, DNMT3B and miR29 may be involved in BL pathogenesis.

Quantitative analysis of CDKN2A methylation, mRNA, and p16(INK4a) protein expression in children and adolescents with Burkitt lymphoma: biological and clinical implications.

CDKN2A is a tumor suppressor gene critical in the cell cycle regulation. Little is known regarding the role of CDKN2A methylation in the pathogenesis of Burkitt lymphoma (BL). CDKN2A methylation was investigated using pyrosequencing in 51 tumor samples. p16(INK4a) mRNA and protein levels were measured using real-time PCR and immunohistochemistry, respectively. CDKN2A methylation was detectable in 72% cases. Nuclear expression of p16(INK4a) was not detected in 41% cases. There was an association between methylation and absence of CDKN2A mRNA (P=0.003). In conclusion, CDKN2A methylation occurs at a high frequency suggesting a role in BL pathogenesis and potential therapeutic implications.

Langerhans cell histiocytosis: differences and similarities in long-term outcome of paediatric and adult patients at a single institutional centre.

PURPOSE: This study determined the frequency of clinical features, reactivations, sequelae, mortality, and overall survival (OS) and compared paediatric with adult Langerhans cell histiocytosis (LCH) patients. MATERIALS AND METHODS: Ninety patients (60 paediatric and 30 adults) with LCH treated during 28 years were analysed retrospectively. RESULTS: Craniofacial lesion was the most frequent lesion at LCH presentation in children and adults. However, some differences were found. Orbital lesions were more frequent in paediatric than adult patients (P = 0.001). There was a tendency for mandible lesions to be more common in adults than the paediatric group (P = 0.0710). Mucocutaneous lesions were observed in a higher proportion in adults compared to paediatric patients (P = 0.0395). Reactivation episodes (36.8 versus 62.5%) and deaths (10.7 versus 24.0%) occurred in lower proportions in paediatric than adult patients, respectively. The probability of OS in 10 years for both groups was similar (P = 0.137). CONCLUSION: The OS was similar in both groups despite clinical differences between paediatric and adult patients, and higher reactivation and death rates in adults.

Histone deacetylase inhibitor prevents cell growth in Burkitt's lymphoma by regulating PI3K/Akt pathways and leads to upregulation of miR-143, miR-145, and miR-101.

Burkitt lymphoma (BL) is an aggressive B-cell lymphoma more common in children comprising one third of pediatric non-Hodgkin lymphoma cases. The recent discovery in BL pathogenesis highlighted the activation of PI3K pathway in cooperation with Myc in the development of BL. In this study, we demonstrated that PI3K/Akt pathway is a target to histone deacetylase inhibitor (HDACi) in BL cells. The combination of HDACi (sodium butyrate, NaB) and chemotherapy (VP-16) inhibited 51 % of the proliferation and enhanced the blockage of the cell cycle progression at G2/M with a concurrent decrease in the S phase. Microarray profiling showed a synergistic action of NaB/VP-16 combination through the differential regulation of 1,413 genes. Comparing VP-16 treatment with the NaB/VP-16 combination, 318 genes were deregulated: 250 genes were downregulated, and 68 were upregulated when compared with untreated cells. Among these genes, six (CDKN1A, CCND1, FAS, CHEK2, MDM4, and SESN2) belong to the p53-signaling pathway. The activation of this signaling pathway is usually induced by stress signals and ultimately leads to cell cycle arrest. Besides, the inhibition of the cell growth was related to reduced Akt phosphorylation, and decrease of c-Myc protein expression by about 60 % (p ≤ 0.005). Moreover, HDACi enhanced miR-101, miR-143, and miR-145 levels in BL cell line, which were inversely associated with the levels of miR-101, miR-143, and miR-145 found to be extremely downregulated in the sample of BL patients. We highlight the fact that effective combinations of HDACis with other target drugs could improve BL therapy in the future.

Immunohistochemistry expression of TCF4 protein on carcinoma, adenoma and non neoplastic colorectal mucosa / Expressão imuno-histoquímica da proteína TCF4 no carcinoma, no adenoma e na mucosa não neoplásica colorretal

PURPOSE: To detect and quantify the immunoreactivity of TCF4 protein in colorectal carcinoma, colorectal adenoma and non-neoplasic colorectal epithelium. METHODS: We studied 129 individuals: 40 with colorectal cancer, 52 with colorectal adenoma and 37 with non-neoplastic colorectal epithelium. The colorectal adenoma and carcinoma samples were obtained from patients who underwent surgical procedures, and colonoscopies and samples of non-neoplastic colorectal epithelium were taken from patients who died from cardiovascular diseases, without diseases of the large intestine. Samples of different tissues were included in paraffin blocks, and the immunohistochemical expression of protein TCF4 was analyzed using the technique of tissue microarray (TMA) with polyclonal antibody TCF4. The immunoreactivity was analyzed and classified as positive and negative. RESULTS: The immunohistochemical expression of TCF4 protein was significantly higher (p < 0.01) in colorectal carcinoma than in the non-neoplastic colorectal epithelium and adenoma. There was no difference (p = 0.76) between TCF4 protein immunohistochemical expression in colorectal adenoma and non-neoplastic colorectal tissue. CONCLUSIONS: TCF4 protein showed a more intense expression in colorectal carcinoma than in non-neoplastic colorectal epithelium and adenoma, indicating that this protein is involved in colorectal carcinogenesis. (AU)

OBJETIVOS: Detectar e quantificar a imunoexpressão da proteína TCF4 no carcinoma e no adenoma colorretal e no epitélio colorretal não neoplásico. MÉTODO: Foram estudados 129 indivíduos: 40 com carcinoma colorretal, 52 com adenoma colorretal e 37 com epitélio colorretal não neoplásico. Os tecidos de adenoma e carcinoma colorretais foram representados por amostras da lesão retirada de doentes submetidos a procedimentos cirúrgicos e colonoscópicos, e as amostras de epitélio colorretal não neoplásico foram retiradas de doentes falecidos por afecções cardiovasculares e sem comprometimento do intestino grosso. As amostras dos diferentes tecidos foram incluídas em blocos de parafina e submetidas ao estudo da imunoexpressão da proteína TCF4 pela técnica do tissue microarray (TMA) com o anticorpo policlonal anti-TCF4. A imunorreatividade foi analisada e classificada como positiva e negativa. RESULTADOS: A imunoexpressão da proteína TCF4 foi significantemente maior (p < 0,01) no carcinoma colorretal do que nos adenomas e no epitélio colorretal não doente. Não houve diferença significante (p = 0,76) entre a imunoexpressão da proteína TCF4 no adenoma colorretal e no epitélio colorretal não doente. CONCLUSÃO: A maior expressão da proteína TCF4 no carcinoma colorretal em relação ao adenoma e ao epitélio não doente sugere que esta proteína possui participação na carcinogênese colorretal. (AU)

Centroblastic diffuse large B cell lymphoma displays distinct expression pattern and prognostic role of apoptosis resistance related proteins.

Centroblastic diffuse large B cell lymphoma (DLBCL) samples were analyzed by immunohistochemistry to evaluate the expression of p53, Bcl-2, Survivin, XIAP, and Ki-67. Survivin was the only protein which expression exhibited a trend for impact in progression-free (p = .077) and overall survival (p = .054). In the Mann-Whitney test, Survivin expression correlated with a negative overall survival (p = .045). These results appeared to be intimately related to Survivin cytoplasmic localization. Moreover, the anti-apoptotic proteins Bcl-2 and Survivin were less frequent in centroblastic DLBCL. Our results indicate that centroblastic DLBCL may be a disease with characteristic biology and clinical course and, therefore, specific prognostic factors.

Hormone receptors: association with prognostic factors for breast cancer

Os tumores de mama positivos para receptores de estrogênio (RE) e/ou de progesterona (RP), além de apresentarem um prognóstico mais favorável, mostram associações com outras variáveis de bom prognóstico. A partir de um estudo com 306 carcinomas ductais infiltrantes de mama, foram construidos modelos preditivos para a positividade dos RE e dos RP. Foram estudadas variáveis relacionadas às pacientes e ao tumor (características macro e microscópicas e marcadores tumorais processados por imuno-histoquímica). Na análise bivariada, algumas variáveis se associaram estatisticamente com a positividade dos RE e RP, porém, na regressâo logística não condicional somente as seguintes variáveis foram fatores preditivos independentes: idade da paciente (RE e RP), idade da menarca (RP), grau histológico (RE e RP), RP (RE) e p53 (RE). De acordo com os resultados deste estudo as variáveis idade da paciente ao diagnóstico, grau histológico, RP e p53 foram fatores preditivos para a positividade dos RE, enquanto que a idade da paciente, a idade da menarca e o grau histológico o foram para os RP.

Adenoma hiperfuncionante de paratireoide: relato de um caso / Hyperfunctioning parathyroid adenoma: a case report

É crescente o interesse no emprego dos métodos de imagem durante a investigaçäo pré-cirúrgica dos pacientes com hiperparatireoidismo primário. Os autores relatam um caso de adenoma hiperfuncionante da paratireóide, que eclodiu com sintomatologia óssea, no qual se empregou a ultrasonografia e a cintilografia com Tc-99m-sestamibi no estudo pré-cirúrgico das paratireóides. Säo apresentados, também, os achados radiológicos, com a utilizaçäo da radiologia convencional e da tomografia computadorizada, bem como o aspecto evolutivo das lesöes, quatro meses após o início do tratamento