Deletion of the gene essential for efficient viralreplication in normal cells (e.g. E1B-55K); making replication dependent on the enzyme highly active only in cancer cells (e.g. human telomerase reverse transcriptase); modification of viral capsid protein (e.g. adding RGD peptide to a fibre capsid protein, deletion in the E1A region, creating chimeric hexon capsid protein with adenovirus serotype rare in nature). Here, DHTKD1 is linked to cancer.