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 miR124a-1, miR124a-2, and miR124a-3 in Hodgkin lymphoma.

Deregulation of the microRNA miR124a by DNA methylation has been implicated in various malignancies, but no study reported its methylation status in Hodgkin lymphoma (HL). We evaluated the methylation of the three loci encoding for miR124a using methylation-specific PCR in 64 HL patients and 15 reactive lymph nodes obtained from patients with nonmalignant diseases. Results were correlated with clinicopathological parameters.

Correlation between DNA methyltransferases expression and Epstein-Barr virus, JC polyomavirus and Helicobacter pylori infections in gastric carcinomas.

It' is accepted that aberrant expression of DNA methyltransferases (DNMTs) is responsible for hypermethylation in genes. However, there are limited data related to factors inducing aberrant expression of DNMTs. A total of 43 surgically resected gastrc carcinomas (GC) samples were analysed.