It is intended to provide a drug to be used in gene therapy which specifically targets abnormal cells such as tumor cells and destroys the same for healing. Namely, a drug comprising, as the active ingredient, a proliferative vector which contains a Survivin promoter proliferating depending on the expression of Survivin. The drug may be used in order to treat tumor. In this drug, use may be made of an adenovirus as the vector. In the adenovirus of this drug, an endogenous promoter of an E1A domain may be substituted with a Survivin promoter.
