SinceDNAH11is not expressed in malignant plasma cells, and rs4487645 represents the strongest signal for MM at 7p15. 3, the data are collectively consistent with this eQTL being the functional basis of the association. CDCA7Land c-Myc actually interact by the conserved leucine zipper domain name ofCDCA7Land the c-Myc NH2-terminal domain. 9CDCA7Lpotentiates c-Myc transforming activity, and can complement a transformation-defective c-Myc mutant. 10Our data showed thatCDCA7Land MYC expression did not correlate in MM cells. 2p23. three or more, 3p22. 1, 3q26. 2, 6p21. 33, 7p15. three or more, 17p11. 2, and 22q13. 1 influencing MM risk. 1, 2The genetic and functional basis of these organizations have, however , yet to be deciphered. Most GWAS-detected SNPs influencing cancer risk map to non-coding regions of the genome implying that their functional effect is mediated through differential expression rather than change in protein sequence. 3Therefore, study of expression quantitative trait loci (eQTL) provides a means of delineating the basis of GWAS signals. A recently published sequencing study of lymphoblastoid cell lines showed that 28% of 14, 000 genes had one or more eQTLs, implicating inherited variant as an important determinant of gene expression. 4Moreover, 16% of 6500 variants in the disease- and trait-related GWAS catalog (www.genome.gov/gwasstudies/) were identified as eQTLs. 4 In this study, we analyzed eQTL data generated on malignant plasma cells from 848 MM patients to investigate whether MM risk SNPs influence gene expression in MM cells. Collection of samples and clinico-pathological information from patients was undertaken with informed consent and relevant ethical review board authorization in accordance with the tenets from the Declaration of Helsinki. Plasma cells were CD138-purified from bone marrow aspirates because previously released from two case series which had been the subject of a previous GWAS and an additional series of 277 German patients. 1, 2The 665 German MM patients (389 male, mean age 599 years) used for eQTL discovery were patients of the Heidelberg University Clinic and the German-speaking Myeloma Multicenter Group. The 183 UK MM patients (107 male, mean age group 6410 years) had been enrolled in the UK Medical Research Council Myeloma IX trial. Both German and UK patients had been genotyped using Illumina Human OmniExpress-12 v. 1 . 0 arrays. General genotyping quality control assessment was carried out because previously explained, 1, 2and all SNPs and samples presented in this study exceeded the required thresholds. Fluorescencein situhybridization and gene expression profiling of CD138-purified plasma cells using Affymetrix U133 2 . 0 plus arrays Bax inhibitor peptide, negative control were performed because described. 2, 5, 6Quality control was carried out using NUSE and RLE metrics to identify poorly performing arrays, which were excluded from the analysis. 6Expression data have been deposited in ArrayExpress (E-MTAB-2299) and Gene Expression Omnibus (GSE21349). Analyses were undertaken using R (v. 2 . 8). As chip definition file (CDF) we used the Affymetrix U133 2 . 0 plus array custom (CDF) (v. 17) mapping to Entrez genes (http://brainarray.mhri.med.umich.edu/Brainarray/Database/CustomCDF/). Microarray probes binding to polymorphic sites were identified using PiP Finder (http://bit.ly/pipfinder); probes (n=16, 964/313772) were excluded from the CDF using CustomCDF (101 probesets with <3 probes were discarded). Expression data were normalized using GC-RMA. We excluded genes with log2 expression <3. 5 in at least 95% of samples. After QC, and confining our analysis to autosomal genes, expression data of 9116 genes was available. Bax inhibitor peptide, negative control The filtered set was analyzed using probabilistic estimation of expression residuals (PEER) to infer broad variance components in the data. 7For the German analysis, batch effect LSM6 antibody was included as a co-variate. PEER was used to adjust expression data intended for known and hidden intervening variables, such as cytogenetic subgroups. As previously advocated, we set the maximum number of unobserved factors (hidden confounders) to 100 or 25% of the case number; 7more specifically, 100 for Bax inhibitor peptide, negative control the German series and 46 for the UK series. PEER computed residuals of expression were used for eQTL analyses. We analyzed the relationship between MM risk SNPs and expression of genes located within 1 Mb (cis-eQTL analysis), and all other genes (trans analysis) using MatrixEQTL under a linear model. 8In the case of cis-eQTL analyses on the 7.
SinceDNAH11is not expressed in malignant plasma cells, and rs4487645 represents the strongest signal for MM at 7p15
