The present invention relates to a DNA cassette comprising a nucleotide sequence encoding dodecameric TRAIL and a suicide gene nucleotide sequence, a recombinant expression vector comprising the DNA cassette, a recombinant adenovirus prepared by using the recombinant expression vector, a host cell transduced with the recombinant adenovirus, a composition for treating cancer comprising the host cell, and a method for treating cancer comprising the step of administering the composition for treating cancer to a subject. The stem cell therapy coexpressing dodecameric TRAIL and HSV-TK by introduction of the DNA cassette of the present invention has more excellent anticancer effects than the known therapy, and thus can be effectively used in the treatment of many different types of solid tumors and metastatic tumors.