PROBLEMThere are provided induced malignant stem cells capable of
in vitro proliferation that are useful in
cancer research and
drug discovery for
cancer therapy, as well as processes for production thereof,
cancer cells derived from these cells, and applications of these cells.MEANS FOR SOLVINGAn induced malignant
stem cell capable of
in vitro proliferation are characterized by satisfying the following two requirements:(1) having at least one aberration selected from among (a) an aberration of
methylation (high or low degree of
methylation) in a
tumor suppressor gene or a cancer-related genetic region in endogenous
genomic DNA, (b) a somatic
mutation of a
tumor suppressor gene or a somatic
mutation of an endogenous cancer-
related gene in endogenous
genomic DNA, (c)
abnormal expression (increased or reduced / lost expression) of an endogenous
oncogene or an endogenous
tumor suppressor gene, (d)
abnormal expression (increased or reduced / lost expression) of a noncoding
RNA such as an endogenous cancer-related
microRNA, (e)
abnormal expression of an endogenous cancer-related
protein, (f) an aberration of endogenous cancer-related
metabolism (
hypermetabolism or hypometabolism), (g) an aberration of endogenous cancer-related
sugar chain, (h) an aberration of copy number variations in endogenous
genomic DNA, and (i)
instability of microsatellites in endogenous genomic
DNA in an induced malignant
stem cell; and(2) expressing genes including POU5F1
gene, NANOG
gene, SOX2
gene, and ZFP42 gene.