It is associated with self‐renewal capacity, tumorigenicity, chemoresistance, invasiveness, tumour angiogenesis and metastasis.16, 17, 18, 19, 20, 46 In addition, a higher expression of the CSC markers Nanog and Oct‐4 could be observed, which are known to be preferentially co‐expressed in CD133+ HCSCs and to be involved in the induction of EMT.1, 17, 47, 48 To confirm the stemness state and analyse the potentially correlated tumour cell aggressiveness of the spheroid‐derived HepG2 clones 3 and 5, several functional assays were performed in vitro and in vivo. This evidence concerns the gene PROM1 and neoplasm.