Diffuse Large B Cell Lymphoma Shows Distinct MethylationProfiles of the Tumor Suppressor Genes among theNon-Hodgkin’s Lymphomas

다국어 초록 (Multilingual Abstract)

Aberrant methylation of CpG islands in promoter regions is one of the major
mechanisms for silencing of tumor suppressor genes in various types of human cancers including
non-Hodgkin’s lymphomas (NHL). In this study, we investigated the aberrant promoter
methylation status of known or suspected tumor suppressor genes in NHLs and compared
the methylation profiles between B-cell and T/NK-cell NHLs. Methods : 54 cases of B-cell NHLs
and 16 cases of T/NK-cell NHLs were examined for the methylation status of eight genes
using methylation specific PCR. Results : CpG islands methylation was variously found in
eight genes as follows; DAPK (71%), MT1G (70%), p16 (53%), CDH1 (53%), THBS1 (56%),
MGMT (27.1%), COX2 (13%), and RUNX3 (11.4%). In six cases (8 %), methylation was not
observed in any of these genes. Overall methylation index of B-cell NHLs (0.48) was significantly
higher than that of T/NK-cell NHLs (0.32). Of eight genes tested, THBS1 and CDH1
methylations were much more prominent in diffuse large B-cell lymphomas than in T/NK-cell
NHLs or other B-cell NHLs. Conclusion : This study suggests that aberrant CpG island methylation
is a frequent event in NHLs, and diffuse large B-cell lymphomas show overlapping but
distinct methylation profiles.

다국어 초록 (Multilingual Abstract)

Aberrant methylation of CpG islands in promoter regions is one of the major
mechanisms for silencing of tumor suppressor genes in various types of human cancers including
non-Hodgkin’s lymphomas (NHL). In this study, we investigated the aberrant promoter
methylation status of known or suspected tumor suppressor genes in NHLs and compared
the methylation profiles between B-cell and T/NK-cell NHLs. Methods : 54 cases of B-cell NHLs
and 16 cases of T/NK-cell NHLs were examined for the methylation status of eight genes
using methylation specific PCR. Results : CpG islands methylation was variously found in
eight genes as follows; DAPK (71%), MT1G (70%), p16 (53%), CDH1 (53%), THBS1 (56%),
MGMT (27.1%), COX2 (13%), and RUNX3 (11.4%). In six cases (8 %), methylation was not
observed in any of these genes. Overall methylation index of B-cell NHLs (0.48) was significantly
higher than that of T/NK-cell NHLs (0.32). Of eight genes tested, THBS1 and CDH1
methylations were much more prominent in diffuse large B-cell lymphomas than in T/NK-cell
NHLs or other B-cell NHLs. Conclusion : This study suggests that aberrant CpG island methylation
is a frequent event in NHLs, and diffuse large B-cell lymphomas show overlapping but
distinct methylation profiles.

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