Functional analysis to elucidate the susceptibility mechanisms of SNPs at the REL, GATA3 and TCF3 Loci in classical Hodgkin Lymphoma

Genome Wide Association Studies (GWAS) revealedsignificant associations for SNPs mapping at the REL, GATA3 andTCF3 loci with cHL susceptibility. In this study, we aim to elucidatethe susceptibility mechanism of these associations by establishingpossible expression quantitative trait loci (eQTL) effects. Methods.EQTL analysis was performed in EBV transformed lymphoblastoidcell lines (LCLs) generated from 96 controls and 70 former cHLpatients as well as in three previously published large gene expressionstudies of HRS cells and total HL tissue samples. Results. An eQTLeffect for REL was found using cHL total tissue array data withincreased REL expression levels for individuals carrying the homozygousrisk allele. No significant effects were observed for the HRS celldata and for the LCLs. For GATA3 a significant association was foundhaematologica | 2016; 101(s5) | 5Cologne, Germany, October 22-25, 2016in the patient derived LCLs with lower GATA3 levels in LCLs ofhomozygous risk allele carriers, while no effect was observed for thecontrol LCLs, or the HRS cell and the cHL total tissue array data. OnlyIn the control LCLs lower TCF3 expression levels were found for individualshomozygous for the risk allele. To identify the downstreamtargets of these three transcription factors we performed gene expressionarrays of cHL cell lines infected with shRNA constructs. We identified1805, 1052, 1602 differentially expressed genes for REL, GATA3and TCF3, respectively. eQTL analysis of the array data focusing onlyon these downstream targets is ongoing. Conclusions. For REL, GATA3and TCF3 we observed an eQTL effect in at least one of the studiedgroups. For REL and TCF3 the eQTL pattern is consistent with theproposed susceptibility effects of these genes, i.e. higher REL levelsstimulating cell growth and lower TCF3 levels supporting the lossof-B-cellphenotype for the risk alleles. Surprisingly, for the T-helper2 specific transcription factor GATA3 the risk allele is associated withdecreased levels in B-cells, but apparently not in T-cells. Our data supporta functional rol for the risk and protective SNP alleles in cHL susceptibility