The purpose of the present study was to investigate whether deletions of GSTT1 and GSTM1 as well as GSTP1 Ile- 105Val single nucleotide polymorphism influence clinical presentation, response to therapy and outcome in patients with diffuse large B-cell lymphoma (DLBCL).
In this study, we investigated the influence of the genetic polymorphisms GSTM1, GSTT1, and GSTP1 on treatment response in 94 Korean patients with de novo diffuse large B-cell lymphoma, who had received rituximab plus cyclophosphamide/doxorubicin/vincristine/prednisone (R-CHOP) as a front-line regimen.
Patients with nodal diffuse large B-cell lymphomas (DLBCL) at a single institute (n=44) were studied for methylation of tumor-related genes, MGMT, p15(INK4B), p16(INK4A), p16(INK4A), Mad2, TMS1/ASC, CASP8, and GSTP1.
Genomic DNA and total RNA extracted from frozen samples of DLBCL were analyzed by methylation-specific polymerase chain reaction and quantitative reverse transcription polymerase chain reaction (RT-PCR) to determine promoter hypermethylation and mRNA expression of GSTP1, MGMT, and DAPK.
Individuals with GSTP1 Val homozygotes had non-significant excessive risk of marginal zone lymphoma (OR = 1.8; 0.6-5.1) and 'other' B-cell NHLs (OR = 1.6; 0.7-3.6), but lower risk of diffuse large B-cell lymphoma (OR = 0.2; 0.1-0.96).
Finally, the frequency of GSTP1 aberrant methylation in diffuse large B-cell lymphoma prompts studies aimed at verifying the prognostic impact of this epigenetic lesion in these lymphomas.