DNA methylation patterns in EBV-positive and EBV-negative Hodgkin lymphomas.

Purpose: Hodgkin lymphoma (HL) is characterized by the presence of Hodgkin and Reed-Sternberg cells. Epstein-Barr virus (EBV) infection is thought to play an important role in the development of HL. Although epigenetic alterations, such as aberrant DNA methylation, are known to contribute to the pathogenesis of various malignancies, little is known about such alterations in HL and their putative relationships with EBV infection.

Investigation of miR9-1, miR9-2 and miR9-3 Methylation in Hodgkin Lymphoma.

Background: miR9 is an important tumor suppressor microRNA regulated by DNA methylation in various types of cancers.

Methods: We analyzed the methylation status of the 3 members of the miR9 family in 58 cases of Hodgkin lymphoma (HL) in comparison to 15 reactive lymph nodes. We also assessed the relationships between miR9 methylation and Epstein-Barr virus (EBV) infection and several clinicopathological parameters.

Increased DNA methyltransferase 1 protein expression correlates significantly with intestinal histological type and gender in gastric carcinomas.

Purpose: Promoter hypermethylation and reduced expression of many genes have been found in gastric cancer. DNA methyltransferases are enzymes potentially affecting promoter hypermethylation.

Material And Methods: We analyzed proteins expression of DNA methyltransferase 1 and 3b by immunohistochemistry in 47 surgically resected gastric cancer samples for which clinicopathological characteristics, patient's outcome and methylation status of 11 selected tumor-related genes have been determined.

Methylation of miR-124a-1, miR-124a-2, and miR-124a-3 genes correlates with aggressive and advanced breast cancer disease.

Aberrant DNA methylation on CpG islands is one of the most consistent epigenetic changes in human cancers, and the process of methylation is catalyzed by the DNA methyltransferases DNMT1, DNMT3a, and DNMT3b. Recent reports demonstrate that deregulation of miR-124a, one of the frequently methylated microRNAs in human cancers, is related to carcinogenesis. The aim of this study was to evaluate the frequencies of methylation of the three genomic loci encoding the miR-124a in primary breast cancers and to investigate their relationships with the clinicopathological characteristics of the tumors and with the expression levels of DNMT1, DNMT3a, and DNMT3b.

Clinicopathologic significance of DNA methyltransferase 1, 3a, and 3b overexpression in Tunisian breast cancers.

DNA methyltransferase 1, 3a, and 3b affect DNA methylation, and it is thought that they play an important role in the malignant transformation of various cancers. The current study was designed to analyze DNA methyltransferase expression by immunohistochemistry in a series of 94 Tunisian sporadic breast carcinomas. Results were correlated to clinicopathologic parameters and promoter methylation status of 8 tumor suppressor genes (BRCA1, BRCA2, RASSFA1, TIMP3, CDH1, P16, RARβ2, and DAPK).

Investigation of human JC and BK polyomaviruses in breast carcinomas.

We have previously showed the presence of the simian virus 40 (SV40) and the mouse mammary tumor virus (MMTV)-like in a significant proportions of Tunisian breast carcinomas. However, to date there are no published studies concerning evaluation of the possible implication of the human polyomaviruses JC (JCV) and BK (BKV) in breast carcinomas. The presence of JCV and BKV DNA was investigated by PCR in a 123 primary breast carcinomas and matched adjacent non-tumor breast tissues.

Investigation of Epstein-Barr virus in breast carcinomas in Tunisia.

Breast carcinoma is a major cause of death among women, and the potential implication of viruses in its pathogenesis remains worth a hypothesis. The potential role of Epstein-Barr virus (EBV) in its pathogenesis is still a subject of continued discussion and investigation. The aim of this study was to evaluate the prevalence of EBV in sporadic breast cancers in Tunisia, and to determine the clinicopathological characteristics of virus-positive cases.

Investigation of human papillomavirus in bladder cancer in a series of Tunisian patients.

The association between human papillomavirus (HPV) infection and development of bladder cancer is variable. Furthermore, the prevalence of HPV DNA in bladder carcinoma subtypes varies from study to study. To clarify the impact of HPV infection on the development of bladder carcinoma, we performed a retrospective study on Tunisian patients to determine the status of HPV infection in urothelial carcinoma, squamous cell carcinoma, and adenocarcinoma.

Prevalence and characteristics of Epstein-Barr virus-associated gastric carcinomas in Tunisia.

Objective: Epstein-Barr virus (EBV) has been linked to gastric carcinoma (GC) with worldwide geographical variations of prevalence ranging from 1 to 18% of cases. Investigations carried out in north Africa have shown that some EBV-associated types of cancers are common in this area. This study was taken to determine the prevalence of EBV-associated GC in Tunisia.