The selective replication in tumour cells is achieved by the creation of conditionally replicative adenoviral vectors (CRAdV) lacking E1B-55K and 24-amino acid of the CR2 domain of E1A, because in that case, the virus can preferentially replicate in cancer cells, known to carry p53 mutation and an excessive amount of E2F transcription factor, which complement AdV replication. This evidence concerns the gene DHTKD1 and neoplasm.