Human chondrosarcoma cell lines CS-1 (a gift from Dr. Francis Hornicek, Harvard Medical School, Boston, MA) and JJ (a gift from Dr. Joel Block, Rush Medical School, Chicago, IL) cultured with 10% FBS in a humidified incubator (NuAire Inc, Plymouth, MN) under 5% CO2 and normoxia (ambient oxygen) as previously described (11 (link);18 (link);19 (link)). CS-1 was derived from grade III and JJ from grade II human chondrosarcomas respectively; both metastasize in a xenograft mouse model. (11 (link);19 (link);20 (link)). The CS-1 cell line was authenticated using short tandem repeat (STR) profiling (ATCC, Manassas, VA) in September 2012, matched the STS profiling performed by the source laboratory in 2011, and there were no other matches in the ATCC data base. JJ was authenticated using STR profiling on the source cell line in 1999, 2007, and repeated in 2012. There is 94% similarity between the different time points, the cells are human, and there are no matches with any cell lines in the ATCC database. Frozen aliquots of cells were used for this study.