(続き)
After culturing in ACTH medium for 7 days, this growing population of cells, unlike parental STAP cells, could be passaged as single cells (Fig. 5a, bottom, and Fig. 5b), grow in 2i medium (Extended Data Fig. 8a) and expand exponentially, up to at least 120 days of culture (Fig. 5c; no substantial chromosomal abnormality was seen; Extended Data Fig. 8b, c). Hereafter, we refer to the proliferative cells derived from STAP cells as STAP stem cells.