A method for converting animal cells into brown adipose tissue cells is provided that includes transforming the animal cells using an expression vector. The expression vector includes a nucleotide sequence encoding HB-EGF operatively linked to a promoter and a nucleotide sequence encoding ADAM 12 operatively linked to a promoter. Converting animal cells to brown adipose tissue cells can be used to treat obesity or to treat cancer by converting target cells to brown adipose tissue cells.