“…4 Since the g 1 34.5 gene is responsible for the neurovirulence of HSV-1, 5,6 g 1 34.5 gene-deficient mutants are considered to be useful vectors for oncolytic therapy. So far, a number of malignant tumors including breast cancer, 7 prostate cancer, 8 lung cancer, 9 ovarian cancer, 10 malignant melanoma, 11 malignant glioma, 12 pancreatic cancer, 13 and head and neck cancer, 14,15 have been tested for sensitivity to oncolytic therapy using g 1 34.5 gene-deficient mutants. Despite encouraging preclinical studies, results from clinical trials suggest that current oncolytic viruses, although safe, exert only limited antitumor activity on their own.…”