The present invention is a method for transdifferentiating differentiated cells, comprising contacting at least one element (i) and at least one element (ii) with the cell, wherein the element (i) (A) a polypeptide comprising at least one domain selected from the group consisting of a BH1 domain, a BH2 domain, a BH3 domain and a BH4 domain； (b) an amino acid sequence of a wild type or a fragment thereof of a Bcl-2 family member A polypeptide comprising or consisting of said amino acid sequence； (c) a polypeptide comprising or consisting of the amino acid sequence of a Bcl-2 family member wild type or fragment thereof, wherein said wild type or fragment thereof Said polypeptide comprising one or more point mutations as compared to (d) Bcl-2 Lee's wild type, human Bcl-2 (SEQ ID NO: 1 or 5), human Bcl-XL (SEQ ID NO: 6), human Bcl-w (SEQ ID NO: 7), human Mcl1 (SEQ ID NO: 8), Human BfI1 (SEQ ID NO: 9 or 10), human Nrh (SEQ ID NO: 11), human Bcl2L1 (SEQ ID NO: 12), human DIVA (SEQ ID NO: 13), human myeloid cell leukemia sequence 1 isoform 1 (SEQ ID NO: 14), and Preferably comprising the amino acid sequence comprising at least 30% sequence identity with the wild type of a member of the Bcl-2 family, preferably selected from the group consisting of human Bcl-xβ (SEQ ID NO: 15) A polypeptide； said wild type has anti-apoptotic activity； a nucleic acid encoding said polypeptide, and said cell in said cell Selected from means for increasing the amount and / or activity of a polypeptide, said element (i) improves the yield of transdifferentiated cells by at least 30% compared to when said element (i) is absent, and The element (ii) is selected from a transcription factor capable of transdifferentiating the cell, a nucleic acid encoding the transcription factor, and a means for increasing the amount and / or activity of the transcription factor in the cell Any method of therapeutically treating the human or animal body is excluded. Surprisingly, transdifferentiation is inhibited
