EP300 single nucleotide polymorphism rs20551 correlates with prolonged overall survival in diffuse large B cell lymphoma patients treated with R-CHOP.

BACKGROUND: Rituximab combined with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) is used as standard frontline regimen for diffuse large B-cell lymphoma (DLBCL). The landscape of somatic mutations in DLBCL revealed that inactivation of EP300 plays an important role in lymphomagenesis. A common EP300 single nucleotide polymorphism (SNP) rs20551 results in the substitution of valine for isoleucine at codon 997 close to the Bromodomain. However, the association between SNP rs20551 and clinical prognosis in DLBCL patients treated with R-CHOP is unknown.

METHODS: In this study we analyzed the EP300 SNP rs20551 and prognosis of 226 DLBCL patients who treated with R-CHOP or R-CHOP-like regimes from 2002 to 2013. Determination of the EP300 SNP rs20551 from genomic DNA was obtained by Sanger chain termination sequencing.

RESULT: In this study, the frequency of the A and G allele of the EP300 SNP rs20551 in 226 patients were 92.5 and 7.5%, respectively. We did not observe obvious correlation between patients' disease features and the EP300 SNP rs20551. But the patients with genotype AA had a higher 5-year overall survival rate than those with genotype GA (77.0% vs. 64.7%, p = 0.045). Furthermore, multivariate Cox regression analysis showed that the GA genotype of EP300 SNP rs20551 was an independent poor prognostic factor for DLBCL patients treated with Rituximab-chemotherapy (p = 0.009, HR 2.956, 95% CI 1.315-6.645).

CONCLUSION: This study suggests that EP300 SNP rs20551 might be a useful biomarker to predict the long-term outcome of R-CHOP in DLBCL patients.