A recent large genome-wide association study confirmed the important role of the major histocompatibility complex in classical Hodgkin Lymphoma (cHL) susceptibility (rs6903608), but also identified significant associations with genetic variants outside of the HLA region at chromosomal regions 2p16.1 (REL, rs1432295), 8q24.21 (PVT1, rs2608053, rs2019960), and 10p14 (GATA3, rs501764, rs485411). These single nucleotide polymorphisms (SNPs) are localized in or near important genes involved in lymphoma pathogenesis: REL, which encodes for c-rel, is a member of NFkB pathway; PVT1, which is downstream of the MYC locus, encodes for non-coding microRNAs, some of which have oncogenic properties; and GATA3, which is a critical transcriptional factor for priming lymphoid T-cells for Th2 phenotype, is aberrantly expressed in HL. We investigated whether these six SNPs described in cHL etiology also influence the outcome of newly diagnosed cHL patients in two independent cohorts.
The first cohort consisted of 342 cHL patients from the Groupe d'Etude des Lymphomes de l'Adulte (GELA) who were prospectively enrolled between 1998 and 2002. The second cohort consisted of 259 patients prospectively enrolled in the University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER). DNA for genotyping was extracted from a blood samples collected at diagnosis, and genotyping was conducted using Taqman technology (ABI Prism 7000, Applied Biosystems) for HLA-DRA, PVT1, GATA3 and PCR-based restriction fragment length polymorphism for REL in GELA cohort and Illumina iSelect for the 6 SNPs in MER cohort. Both cohorts were followed for disease progression, re-treatment and death. In the GELA series, the median age was 32 years (range, 15–93), 57% were male, and 72% had an Ann Arbor stage I–II. Histology was nodular sclerosis in 84%, and 29% of available cases (n=40/140) were EBV positive. In the MER series, the median age was 38 years (range, 18–89), 53% were male, and 53% had an Ann Arbor stage I-II. Nodular sclerosis was the most common subtype (62%) and 23 of 115 available cases were EBV positive (20%). The International Prognostic Score (IPS) was 0–1 in 46% and 52% of GELA and MER patients, respectively. ABVD regimen was used for 60% and 88% of the GELA and MER patients, respectively. The 5-year progression free survival (PFS) was 83% and 75% in GELA and MER cohorts, respectively. We estimated the prognostic value of each individual SNP for PFS for allelic and genotypic (dominant and recessive) modes of transmission in each series. In order to increase power, we then performed a meta-analysis of the two studies.
Consistent with prior reports, the minor allele frequencies for REL (rs1432295), HLA-DRA (rs6903608), PVT1 (rs2608053), PVT1 (rs2019960), GATA3 (rs501764) and GATA3 (rs485411) were 0.44, 0.50, 0.43, 0.29, 0.22, 0.28 in the GELA and 0.46, 0.41, 0.46, 0.27, 0.25, 0.31 in the MER series, respectively. In GELA, GATA3 (rs501767) was associated with PFS in the ordinal model (HR=1.66, 95%CI 1.11–2.49, P=.01), while there were suggestive associations for PVT1 (rs2608053) (HR=1.76, 95%CI 0.95–3.26, P=.07) and REL (rs1432295) (HR=0.63, 95%CI 0.37–1.06, P=.08) in the dominant model. In the MER, PVT1 (rs2608053) was associated with PFS in the ordinal model (HR=1.42, 95%CI 0.99–2.03, P=.06), while there was a suggestive association with HLA-DRA (rs6903608) in the dominant model (HR=0.64, 95%CI 0.39–1.05, P=.08) for whole cohort but also for EBV negative cHL (HR=0.41, 95%CI 0.17–0.99, P=.05). In a meta-analysis of the two studies, PVT1 (rs2608053) was significantly associated with PFS in the ordinal (HR=1.34, 95%CI 1.04–1.73, P=.02) and the dominant (HR=1.88, 95%CI 1.20–2.95, P=.006) models. Further adjustment for IPS had minimal impact on these associations (ordinal HR=1.30, 95%CI 1.00–1.70; dominant HR=1.78, 95%CI 1.13–2.83). Patients with PVT1(rs2608053) GG, GA, AA genotypes had a 5-year PFS rate of 83%, 74% and 73% in GELA and 86%, 70%, and 73% in the MER, respectively.
The non-HLA cHL susceptibility locus PVT1 (rs2608053) was associated with PFS in two independent cohorts of cHL cases, and after adjustment for the IPS. While associations with GATA3 and REL were only observed in one of the studies, their evaluation in other studies is warranted. Functional studies of PVT1 in cHL pathogenesis should be pursued.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.