Frequency of aberrant promoter methylation of p15INK4b and O6-methylguanine-DNA methyltransferase genes in b-cell non-Hodgkin lymphoma: A pilot study

The methylation status of the target promoter sequences of p15INK4B (p15) and O6-methylguanine-DNA methyltransferase (MGMT) genes was studied by methylation-specific PCR in 10 adult patients with de novo B-cell non- Hodgkin lymphoma (B-NHL). The aberrant hypermethylation of the p15 gene was more frequent (50%) compared to the hypermethylation of the MGMT gene (30%), and was detected in different types of B-NHL in both genes. Hypermethylation of the MGMT gene occurred exclusively in association with the hypermethylation of the p15 gene. All lymphoma patients with hypermethylation of the p15 and/or MGMT genes had a higher clinical stage of the disease (IV - V). We show the association of anemia and/or thrombocytopenia with the hypermethylation of the p15 gene, ascribing the p15 gene as a potential prognostic marker in B-NHL. Comethylation of MGMT with the p15 gene represents a novel finding and presents both genes as candidates for future studies of the hypermethylation profiles of B-NHL