The Cover

Adenoviral vectors in which the tumor-specific L-plastin gene promoter (AdLpCDIRESE1A) or the cytomegalovirus early transcriptional promoter (AdCMVCDIRESE1A) was used to govern the expression of the cytosine deaminase chemotherapy sensitization gene linked by an IRES element to the viral E1A gene were injected into either tumor nodules or normal liver. As shown in this photograph, expression of the E1A gene (green color) was seen in the nuclei (red color) of normal hepatic tissue injected with the AdCMVCDIRESE1A vector carrying the cytomegalovirusdriven therapeutic transcription unit, but no E1A expression was seen in normal hepatic tissue injected with the AdLpCDIRESE1A vector carrying the L-plastin promoter. In contrast, E1A expression was observed in tumor tissue injected with both the AdCMVCDIRESE1A and AdLpCDIRESE1A vectors. The AdLpCDIRESE1A vector can be used to target chemotherapy to cancer cells while sparing normal tissues from the effects of chemotherapy. For further details, see Akbulut et al. in this issue.