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


METHODS
We investigated promoter methylation patterns of seven tumor-associated genes in 53 primary HL cases using methylation-specific PCR (MS-PCR). Concomitantly, the EBV infection status was assessed using PCR, in situ hybridization and immunohistochemistry.


RESULTS
The gene promoter hypermethylation frequencies observed were 77.3 % for P16, 58.5 % for RASSF1A, 50.9 % for CDH1, 45.3 % for DAPK, 43.4 % for GSTP1, 37.7 % for SHP1 and 24.3 % for MGMT. SHP1 gene promoter hypermethylation was more frequently observed in patients at extreme ages (i.e., ≤ 15 and >54 years) than in adult patients (p = 0.006) and in patients with B symptoms (p = 0.03). Interestingly, most of the analyzed gene promoters were more frequently hypermethylated in EBV-negative than in EBV-positive cases, in particular the DAPK gene promoter (58 % versus 27 %, p = 0.04). Furthermore, hypermethylation of multiple gene promoters (≥ 3) was encountered more frequently in females than in males (86 % versus 57 %, p = 0.04), whereas EBV-positive cases were more common among males than females (55 % versus 30 %, p = 0.02).


CONCLUSIONS
Our results indicate that epigenetic changes frequently occur in both EBV-positive and EBV-negative HL. The rates of these changes were found to vary according to clinico-pathological parameters. These observations probably reflect the multitude of factors involved in HL development and the complexity of their interactions with genetic and/or hormonal factors.
Department of Pathology, CHU Farhat-Hached, Sousse, Tunisia.
Myriam Ben
MB
Dhiab
Department of Pathology, CHU Farhat-Hached, Sousse, Tunisia.
Sonia
S
Ziadi
Department of Pathology, CHU Farhat-Hached, Sousse, Tunisia.
Sarra
S
Mestiri
Department of Pathology, CHU Farhat-Hached, Sousse, Tunisia.
Riadh Ben
RB
Gacem
Department of Pathology, CHU Farhat-Hached, Sousse, Tunisia.
Feryel
F
Ksiaa
Department of Pathology, CHU Farhat-Hached, Sousse, Tunisia. m_trimech@yahoo.fr.
Mounir
M
Trimeche
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D019175:DNA Methylation / Q000235:genetics*; D020031:Epstein-Barr Virus Infections / Q000150:complications*; D005260:Female; D006689:Hodgkin Disease / Q000235:genetics* / Q000821:virology*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics; D055815:Young Adult
Epstein-Barr virus; Hodgkin lymphoma; Methylation