- Multimodality therapy with a replication-conditional herpes simplex virus 1 mutant that expresses yeast cytosine deaminase for intratumoral conversion of 5-fluorocytosine to 5-fluorouracil. Nakamura, H., Mullen, J.T., Chandrasekhar, S., Pawlik, T.M., Yoon, S.S., Tanabe, K.K. Cancer Res. (2001)