In order to analyze the antitumor activity of CIMVs-TRAIL, MCF-7 breast cancer cells were incubated with native CIMVs, CIMVs-BFP, or CIMVs-TRAIL for 24 h and 72 h, next the viability of tumor cells was analyzed by flow cytometry and the expression level of apoptosis regulator genes CASP8, BCL-2 and BAX was determined by qPCR. The gene discussed is CASP8; the disease is breast cancer.