PROM1 and nasopharyngeal carcinoma: FACS analysis was performed to determine the percentage of CD133+SSEA4− NPC population, which ranged from 93.42% to 97.97% in six lines of ASPA iNPCs, and confirmed the lack of residual iPSCs in ASPA iNPCs (0–0.004% by SSEA4 FACS and <0.003% by REX1 RT‐qPCR) (Figure 1E).