Reagent	Type	Manufacturer	Catalog #	Comments
EWS-FLI1 transformed mouse mesenchymal progenitor cells (MPCs)	Cell line	Authors	N/A	Provided by the Stamenkovic lab
FUS-CHOP transformed mouse mesenchymal progenitor cells (MPCs)	Cell line	Authors	N/A	Provided by the Stamenkovic lab
SK-N-MC cells	Cell line	ATCC	HTB-10	Source shared during communication with authors.
Olaparib	Inhibitor	Selleck Chemicals	S1060	Source shared during communication with authors.
DMSO	Chemical	Sigma	D8418	Source shared during communication with authors.
4% formaldehyde	Chemical	USB	19943	Source shared during communication with authors.
Syto60 fluorescent nucleic acid stain	Chemical	Invitrogen	S11342	Catalog # shared during communication with authors.
FBS	Cell culture	Valley Biomedical	BS3032	Original source not specified.
RPMI 1640 medium	Cell culture	ATCC	30-2001	Original source not specified.
Fluorescent plate reader	Equipment	LiCor		Source shared during communication with authors.
DMEM, low glucose, GlutaMAX supplement, pyruvate	Cell culture	Gibco	21885-025	Shared during communication with authors.
MCDB 201 medium, with trace elements, L-glutamine and 30 mM HEPES; powder	Cell culture	Sigma	M6770	Shared during communication with authors.
Ascorbic acid-2-phosphate	Cell culture	Sigma	A8960	Shared during communication with authors.
Dexamethasone	Chemical	Sigma	D8893	Shared during communication with authors.
Linoleic acid-BSA	Chemical	Sigma	L9530	Shared during communication with authors.
Insulin, transferrin, sodium selenite supplement	Growth factor	Roche (Sigma)	1074547	Shared during communication with authors.
Dialyzed FCS	Cell culture	Sigma	F0392	Shared during communication with authors.
EGF; human	Growth factor	Sigma	E9644	Shared during communication with authors.
PDGF-BB, rat	Growth factor	R&D Systems	520-BB-050	Shared during communication with authors.
Penicillin-Streptomycin; 100X	Cell culture	Sigma	P4333	Original source not specified.
Leukemia inhibitory factor (LIF); human; 10 µg/ml	Growth factor	Sigma	L5283	Shared during communication with authors. Replaces LIF generated from CHO LIF720D cells.
Fibronectin; 0.1% in PBS	Chemical	Sigma	F1141	Shared during communication with authors.