.....During the isolation and propagation of murine ASCs we observed the appearance of a spontaneously immortalized cell clone, named m17.ASC. This clone has been propagated for more than 180 passages and stably expresses a variety of stemness markers, such as Sca-1, c-kit/CD117, CD44, CD106, islet-1, nestin and nucleostemin. Furthermore these cells can be induced to differentiate towards osteogenic, chondrogenic, adipogenic and cardiogenic phenotypes. m17.ASC clone displays a normal karyotype and stable telomeres, does not proliferate when plated in soft agar, nor give rise to tumors when injected subcutaneously in NOD/SCID gamma null mice. The analysis of gene expression highlighted transcriptional traits of SVF cells. m17.ASCs were genetically modified by lentiviral vectors carrying GFP as a marker transgene and efficiently engrafted in the liver, when injected in the spleen of NOD/SCID gamma null monocrotaline-treated mice. These results suggest that this non-tumorigenic spontaneously immortalized ASC line may represent a useful tool (cell model) to the study differentiation mechanisms involved in tissue repair as well as a model for pharmacological/toxicological studies.