Abstract

Abstract 301

Multiple myeloma (MM) is an incurable B-cell malignancy characterized by the clonal proliferation and accumulation of malignant plasma cells in the bone marrow. Despite the growing number of sequencing studies, the comprehensive view of somatic mutations in multiple myeloma is far from clear. One of the most frequently altered gene families in most human cancer is the Ras and the tyrosine kinase (TK) genes, which encode for important regulators of various signal transduction pathways. To uncover the somatic mutation profile of Ras gene and TKs in myeloma, we performed a systematic mutation screening from a selected group of 10 candidate genes in 42 primary myeloma patients. The candidate gene selections were based on the highly altered genes extracted from GEO data sets using Function Express, a data mining and viewer for microarray data. The sequencing of the entire gene region including the promoter and the 3`UTR was performed in the Genome sequencing center at Washington University medical center using the standard resequencing pipeline, from the design of the primers to data output. These data were analyzed with a clinical resequencing pipeline and visualized using the Mutation Viewer software (MV v5.1). We identified 24 nonsynonymous alterations in five genes (KRAS2, PIK3CA, INSR, LTK and MERTK) in our myeloma cohort (Table 1). In particular, we identified the previously reported pathogenic mutation in a KRAS gene and novel somatic mutations in the Kinase family (PIK3CA) that would be expected to cause structural changes. We assessed the frequency plots of the known variants and most but not all are significantly different from the normal data set. The overall results suggest that the germline genetic background besides the somatically acquired mutations may exert an important influence on the prognosis and outcome of the myeloma patient. Our genome-wide resequencing approach thus revealed previously known and novel oncogenic mutations in multiple myeloma, but its relevance needs to be considered in the context of other genetic abnormalities.

Table 1:

DNA alterations in candidate ras and TK genes in primary multiple myeloma

GeneGene IDaNucleotide changebAmino acid changeZygositycPolyPhenCOSMIC
KRAS2 3845 c.35 G>A p.G12D Hetero P. Dam Yes 
KRAS2 3845 c.34 G>T, c.33 T>C p.G12C, A11A Hetero Benign Yes 
KRAS2 3845 c.183 A>C p.Q61H Hetero P. Dam Yes 
KRAS2 3845 c.186_194 del p.E62_Y64 Homo   
PIK3CA 5290 c.928 C>T p.R310C Hetero  Yes 
PIK3CA 5290 c.1173 A>G p.I391M Hetero Benign  
INSR 3643 c.356 C>T p.A119V Hetero   
INSR 3643 c.2243 C>T p.S748L Hetero   
INSR 3643 c.3034 G>A p.V1012M Hetero P. Dam  
LTK 4058 c.125 G>A p.R42Q Hetero Benign  
LTK 4058 c.680 C>T p.P227L Hetero   
LTK 4058 c.728 G>A p.R243Q Hetero   
LTK 4058 c.1603 G>A p.D535N Hetero   
MERTK 10461 c.60 A>T p.R20S Hetero Benign  
MERTK 10461 c.1552 A>G p.I518V Hetero, Homo Benign  
MERTK 10461 c.1397 G>A p.R466K Hetero, Homo Benign  
MERTK 10461 c.353 G>A p.S118N Hetero, Homo Benign  
MERTK 10461 c.2608 G>A p.V870I Hetero Benign  
MERTK 10461 c.844 G>A p.A282T Hetero Benign  
MERTK 10461 c.1493 A>G, c.1494 C>T p.N498S Hetero Benign  
MERTK 10461 c.878 G>A p.R293H Hetero Benign  
MERTK 10461 c.2593 C>T p.R865W Hetero P. Dam  
MERTK 10461 c.2069 C>T p.T690I Hetero Benign  
MERTK 10461 c.2467 G>C p.E823Q Hetero Benign  
GeneGene IDaNucleotide changebAmino acid changeZygositycPolyPhenCOSMIC
KRAS2 3845 c.35 G>A p.G12D Hetero P. Dam Yes 
KRAS2 3845 c.34 G>T, c.33 T>C p.G12C, A11A Hetero Benign Yes 
KRAS2 3845 c.183 A>C p.Q61H Hetero P. Dam Yes 
KRAS2 3845 c.186_194 del p.E62_Y64 Homo   
PIK3CA 5290 c.928 C>T p.R310C Hetero  Yes 
PIK3CA 5290 c.1173 A>G p.I391M Hetero Benign  
INSR 3643 c.356 C>T p.A119V Hetero   
INSR 3643 c.2243 C>T p.S748L Hetero   
INSR 3643 c.3034 G>A p.V1012M Hetero P. Dam  
LTK 4058 c.125 G>A p.R42Q Hetero Benign  
LTK 4058 c.680 C>T p.P227L Hetero   
LTK 4058 c.728 G>A p.R243Q Hetero   
LTK 4058 c.1603 G>A p.D535N Hetero   
MERTK 10461 c.60 A>T p.R20S Hetero Benign  
MERTK 10461 c.1552 A>G p.I518V Hetero, Homo Benign  
MERTK 10461 c.1397 G>A p.R466K Hetero, Homo Benign  
MERTK 10461 c.353 G>A p.S118N Hetero, Homo Benign  
MERTK 10461 c.2608 G>A p.V870I Hetero Benign  
MERTK 10461 c.844 G>A p.A282T Hetero Benign  
MERTK 10461 c.1493 A>G, c.1494 C>T p.N498S Hetero Benign  
MERTK 10461 c.878 G>A p.R293H Hetero Benign  
MERTK 10461 c.2593 C>T p.R865W Hetero P. Dam  
MERTK 10461 c.2069 C>T p.T690I Hetero Benign  
MERTK 10461 c.2467 G>C p.E823Q Hetero Benign  
a

Gene ID at National center for biotechnology information (http://www.ncbi.nlm.nih.gov/sites/entrez)

b

del., deletion

c

Homo, homozygous; hetero, heterozygous

Disclosures:

No relevant conflicts of interest to declare.

Author notes

*

Asterisk with author names denotes non-ASH members.