The present invention provides a method of producing progenitor cells, such as cells capable of being differentiated into a plurality of different cell types, from differentiated cells. Methods of using progenitor cells in differentiation and/or tissue or organ repair and/or regeneration and/or building are also provides. Methods of using progenitor cells in treatment and prophylaxis of conditions alleviated by administering stem cells or tissue or organ derived from stem cells to a subject or by grafting stem cells or tissue or organ derived from stem cells into a subject or by transplanting stem cells or tissue or organ derived from stem cells into a subject are also provided. Also included are progenitor cells and differentiated cells and/or tissues and/or organs derived therefrom, and kits comprising same.
