DNA methylation of promoter-associated CpG islands is an epigenetic modification of DNA associanted with gene silencing. p73 is a member of the p 53 family which is a tumor suppressor gene producing apoptosis and cell cycel arrest. We investigated the methylation pattern of p73 on the cases diagnosed at Ewha university hospital between 1993-2002.

Sixteen cases of NK/T cell lymphomas and 7 cases of normal controls, which were 2 cases of peripheral blood mononuclear cells and 5 cases of nasal mucosal tissue were studied. Methylation-speific PCR for p73 were done.

All cases of NK/T cell lymphomas except one(93.8%) showed hypermethylation of p73. Six cases among 7 normal control cases(14.2%) revealed unmethylated p73.

This results suggested that inactivation of p73 could be associated with tumorigenesis of NK cells.