Here, the increased expression of survivin and its alternatively spliced survivin-ΔEx3 variant provided for the single, most significant deregulation of apoptotic pathways in Non Responder breast tumors, and recombinant expression of survivin-ΔEx3 was sufficient, alone, to confer doxorubicin resistance in model breast cancer cell types. This evidence concerns the gene BIRC5 and breast neoplasm.