SAS IS AMPLIFIED PREDOMINANTLY IN SURFACE OSTEOSARCOMA

The development of several types of human tumors is related to amplifi cation of genes that are involved in cell growth. The protein products of these genes give the cells a selective growth advantage. The q13-1 5 region of chromosome 12 is frequently altered in human sarcomas, and the SAS gene has been identified in an amplification unit mapping to this region. Gene amplification of SAS was analyzed to determine the f requency of genetic alteration of this gene in osteosarcoma. Using Sou thern blot analysis as well as quantitative polymerase chain reaction. SAS was found to be amplified in 10 (36%) of 28 osteosarcomas. Gene a mplification was evaluated in subtypes of osteosarcoma. All seven surf ace osteosarcomas displayed amplified SAS. In contrast, SAS was amplif ied in only two (13%) of 15 intramedullary osteosarcomas. The finding that all surface osteosarcomas demonstrated SAS gene amplification sug gests that this gene may play a role in the pathogenesis of osteosarco ma subtypes and that surface osteosarcoma may be genetically different from high-grade intramedullary osteosarcoma.