“…Tumor-specific gene expression can be driven by tissue-or tumor-specific promoters, such as the PSA promoter in prostate carcinoma [14], the Chromogranin A promoter in neuroendocrine tumors [15], or the glut1 promoter, which is specific for many neoplastic tissues [16]. Weak tissue specific promoters can be amplified by using strategies such as the two-step transcriptional activation, or the CreYLoxP system [17,18]. Recently, expression of the fLuc gene was detected in lung and bone metastases of prostate tumor cells after a systemic injection of an adenovirus carrying the gene.…”