PROBLEM TO BE SOLVED : To provide an agent for oncolytic treatment of cancer with improved capabilities for lytic destruction and/or gene introduction of tumor cells in vivo.SOLUTION : A therapeutic agent comprises a herpes simplex virus 1 (HSV1) with a gene which (i) lacks a functional ICP34.5 encoding gene, (ii) lacks a functional ICP47 encoding gene, and (iii) comprises a gene encoding an immunostimulatory protein, where the gene is under the control of a promoter, the promoter is a ubiquitous promoter or a viral promoter, and the immunostimulatory protein is a cytokine or human GM-CSF.SELECTED DRAWING : NoneCOPYRIGHT : (C)2019, JPO&INPIT