How long can organoids be expanded in vitro, and what factors determine their longevity?
Generally, organoids can be maintained and expanded in vitro for several weeks to years, with tumor-derived organoids capable of near-indefinite passaging. Their longevity is mainly determined by tissue origin, donor health status, stem cell potency, and culture system optimization. To ensure long-term expansion without genomic instability, marker expression and karyotype analysis are recommended every 5-10 passages. Preserving resident stem cell populations relies on high-potency growth factors and tissue-specific validated culture media.