The invention relates to methods for generating multipotent mammary stern cells from isolated and cultured human breast luminal cells. The method comprises the steps: 1. isolating and growing normal differentiated cells in vitro; 2. treating the differentiated cells with either a conditioned medium from active fibroblasts or cytokine. The invention also relates to multipotent mammary stem cells, cultures of the multipotent stem cells, differentiated cells, tissues, organs derived from the culture multipotent stem cells isolated by the methods disclosed and therapeutic and other uses for those cells thereof.