Colorectal cancer (CRC) is the third most prevalent form of cancer and the second leading cause of cancer-related deaths worldwide. oncolytic virotherapy shows promise as a targeted therapy for various cancer types, including CRC. In this study, we constructed a novel oncolytic herpes simplex virus type 2 (oHSV-2) are derived from the wild type HSV-2, that isolated from semen samples of suspected infertile men. We investigated the effects of oHSV2 in vitro on expression the Carcinoembryonic antigen (CEA) in LS174T colorectal adenocarcinoma cell line model compare with a normal vero cell line. Tumor markers expression monitoring by the enzyme-linked immunosorbent assay (ELISA), of untreated cells and that treated with wHSV-2, oHSV-2 and after treatment with the traditional chemotherapeutic agent 5 flouro uracil 5FU.