Germline Variation in TNF and NF-Kappa B Pathways and Prognosis In Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an aggressive lymphoma. NF-κB has been shown to be constitutively activated in MCL cell lines and patient biopsy samples and may play a key role in the growth and survival of MCL cells. We previously reported in a pilot study of 39 MCL patients from the NCI-SEER Survival Study that host genetic variation in candidate TNF and NF-κB genes was associated with overall survival after accounting for clinical variables (Blood 2007;110(11):472a). Here, we attempt to replicate the top 8 genes (NFKB1, IRF4, TNFSF13B, TNFRSF25, NFKBIA, LTA/TNF, TRAF5, RELB) and associated single nucleotide polymorphisms (SNPs) in an independent sample of MCL patients.

We genotyped 71 SNPs from 8 genes in a prospective cohort of newly diagnosed MCL patients with germline DNA enrolled at the Mayo Clinic and University of Iowa from 2002–2008 as part of the Molecular Epidemiology Resource of the Iowa/Mayo Lymphoma SPORE. All patients were systematically followed through 2009 for overall survival (OS) and event-free survival (EFS, defined as disease progression, retreatment or death due to any cause). Genotyping was performed on an Illumina Golden-Gate platform. Cox regression was used to estimate Hazard Ratios (HRs) and 95% confidence intervals (CI) for individual SNPs with OS and EFS. Each SNP was modeled with the most prevalent homozygous genotype used as the reference group. An ordinal test was used to assess the trend across genotype. A principal components methodology was used for gene-level analyses. All Cox models were adjusted for MIPI and treatment. We compared our results to the previously reported NCI-SEER study that included MCL patients diagnosed from 1998–2000. The NCI-SEER study had a median age at diagnosis of 64 years (range 38–74), 27 deaths (69%), and a median follow-up for living patients of 47 months (23-85 months). Replication was declared based on a p-trend<0.10 in the gene-level test or p-trend<0.10 in the SNP-level ordinal trend test and a HR of similar direction and magnitude to the NCI-SEER study result.

The median age at diagnosis of the 101 patients in the SPORE was 64 years (range 42–88), and by simplified MIPI score there were 38% low risk, 37% intermediate risk, and 26% high risk patients. The most common initial therapy was anthracycline-based chemotherapy ± rituximab (59%) with or without stem cell transplantation. Through 2009, there were 61 events (60%) and 31 (31%) deaths, with a median follow-up for living patients of 59 months (range 29–90). At the gene-level, none of the 8 genes replicated at p<0.10. However, at the SNP level, the genes with SNPs that replicated for OS included TRAF5 (rs3738199, rs6684874, rs12569232), TNFRSF25 (rs3138156), and RELB (rs10424046, rs1560725). The strongest TRAF5 SNP was rs3738199 which had a minor allele frequency (MAF) of 0.35. Compared to patients with the AA genotype, those with the AG (HR=2.14, 95% CI 0.91–5.01) or GG (HR=3.72, 95% CI 1.34–10.3) genotypes had inferior survival (p-trend=0.0092). The TNFRSF25 SNP rs3138156 had a MAF of 0.054; compared to patients with the AA genotype, those with the AG or GG genotype (HR=2.46, 95% CI 0.88–6.89) had inferior survival (p=0.087). Finally, the strongest RELB SNP was rs10424046, and had a MAF of 0.54. Compared to patients with the GG genotype, those with the GC (HR=0.57, 95% CI 0.25–1.28) or CC (HR=0.39, 95% CI 0.14–1.12) genotypes had superior survival (p-trend=0.065). Similar results for EFS were observed for the TRAF5 and RELB SNPs.

Germline genetic variation in the TNF and NF-κB pathway genes TRAF5, RELB, and TNFRSF25 were associated with prognosis in MCL after adjustment for clinical and treatment factors, and this result replicates findings from an independent dataset. TRAF5 is one of the components of a multiple protein complex which binds to TNF receptor cytoplasmic domains and mediates TNF-induced activation; RELB is part of the NF-κB complex; and TNF super family receptor member 25 stimulates NF-κB activity and regulates apoptosis through signal transduction that is mediated by various death domain containing adaptor proteins. In summary, genetic variation in TNF and NF-κB pathway genes may play a role in disease progression and overall survival in MCL, supporting further targeting of this pathway for therapy.

Lymphoma Research Foundation, P50 CA97274, R01 CA129539.

No relevant conflicts of interest to declare.