LSAMP, a novel candidate tumor suppressor gene in human osteosarcomas, identified by array comparative genomic hybridization.
Osteosarcomas are the most common primary malignant tumor of bone, and almost all conventional osteosarcomas are high-grade tumors with complex karyotypes. We have examined DNA copy number changes in 36 osteosarcoma tumors and 20 cell lines using microarray-based comparative genomic hybridization. The most frequent minimal recurrent regions of gain identified in the tumor samples were in 1q21.2-q21.3 (78% of the samples), 1q21.3-q22 (78%), and 8q22.1 (72%). Minimal recurrent regions in 10q22.1-q22.2 (81%), 6q16.1 (67%), 13q14.2 (67%), and 13q21.1 (67%) were most frequently lost. A small region in 3q13.31 (2.1 Mb) containing the gene limbic system-associated membrane protein (LSAMP) was frequently deleted (56%). LSAMP has previously been reported to be a candidate tumor suppressor gene in other cancer types. The deletion was validated using fluorescence in situ hybridization, and the expression level and promoter methylation status of LSAMP were investigated using quantitative real-time reverse transcription PCR and methylation-specific PCR, respectively. LSAMP showed low expression compared to two normal bone samples in 6/15 tumors and 5/9 cell lines with deletion of 3q13.31, and also in 5/14 tumors and 3/11 cell lines with normal copy number or gain. Partial or full methylation of the investigated CpG island was identified in 3/30 tumors and 7/20 cell lines. Statistical analyses revealed that loss of 11p15.4-p15.3 and low expression of LSAMP (both P = 0.011) were significantly associated with poor survival. Our results show that LSAMP is a novel candidate tumor suppressor gene in osteosarcomas.
Department of Tumor Biology, The Norwegian Radium Hospital, Rikshospitalet University Hospital, Oslo, Norway.
Stine H
SH
Kresse
Hege O
HO
Ohnstad
Erik B
EB
Paulsen
Bodil
B
Bjerkehagen
Karoly
K
Szuhai
Massimo
M
Serra
Karl-Ludwig
KL
Schaefer
Ola
O
Myklebost
Leonardo A
LA
Meza-Zepeda
D000293:Adolescent; D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000235:genetics* / Q000378:metabolism; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D002648:Child; D002869:Chromosome Aberrations; D016000:Cluster Analysis; D055028:Comparative Genomic Hybridization / Q000379:methods*; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D003627:Data Interpretation, Statistical; D005260:Female; D058851:GPI-Linked Proteins; D018628:Gene Dosage; D020869:Gene Expression Profiling; D016147:Genes, Tumor Suppressor; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D012516:Osteosarcoma / Q000235:genetics* / Q000378:metabolism; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction
D015816:Cell Adhesion Molecules, Neuronal; D058851:GPI-Linked Proteins; C095362:limbic system-associated membrane protein