CORD-19:02a37452d5c5906b46021fbfa99a96df71704b65 / 14743-15015 JSONTXT

{"project":"Epistemic_Statements","denotations":[{"id":"T40","span":{"begin":0,"end":272},"obj":"Epistemic_statement"}],"text":"Another possibility is that PDGF is only one of a number of factors, including FGF-2 and possibly other as yet unrecog- nised factors, that are required for OP expansion and indicated that growth factor signalling is an importhat OP recruitment can proceed in its absence."}