Use of alternate splicing to identify subgroups in uniformly treated newly-diagnosed myeloma

8602 Gene function is modulated at multiple levels. Besides expression level changes, post-transcriptional changes such as alternate splicing alter specificity of gene function. Misregulation of alternate splicing is associated with various disease processes including cancer. We have analyzed alternate splicing in myeloma (MM) using high throughput exon array analysis. Affymetrix Human Exon 1.0 ST Arrays used in this investigation, besides expression levels, also provides information on presence of each exon and identifies recurrent alternately spliced genes. We evaluated 170 newly-diagnosed patients with MM treated homogeneously in tandem transplantation IFM trials using CD138 purified MM cells. Xray array tool (Biotique systems) and dChip software was modified to analyze exon array data. We first normalized gene-level expression values across samples, and then identified differentially expressed exons to identify alternate splicing events. We observed over 100 genes with alternate splicing in myeloma with frequency in more than 20% patients. Unsupervised hierarchical clustering showed two groups within myeloma patients which differ in overall survival (OS). Dividing the group based on response, 52 alternately spliced exons were identified as influencing response to therapy including CD79A exon 4, XRCC exon 3 and 17, PRKDC exon 4, NIT 2 exon 4, Calmin exon2, MADH1 exon 7, TBX5 exon 2, Amyloid beta exon 14 with the highest frequency of alternate splicing. Amongst these, 32 genes had the most influence on response with over 50% differential frequency in patients achieving CR. Similarly 85 alternately spliced genes are influencing OS between groups at 48 month survival cut-off. 49 genes within this group had the most influence on OS. Shared spliced variants between both response and survival groups suggesting their biological and functional significance. Further validation of these alternate splicing is under investigations. This study highlights that alternate splicing is observed with significant frequency and demand need for evaluation of not only the expression level of genes but also post translational modifications. The spliced genes identified here are important target for therapy as well as possible immune modulation. No significant financial relationships to disclose.