Biopsy specimens obtained immediately prior to the second injection, 5–14 days after the first injection and from the same coordinates, showed decreased number of tumor cells, possibly due to tumor cell destruction associated with viral replication, infiltration of CD4+ and CD8+ T lymphocytes, and HSV-1 positive immunostaining, likely reflecting G47∆ replication (Figs. 2, 3). This evidence concerns the gene CD4 and neoplasm.