DHTKD1 and cancer: In order to solve this problem, we first developed a method for efficient construction of “CRAs that can specifically target tumors with multiple factors (m-CRA)”; the replication of these viruses can be simultaneously regulated by up to four independent factors of the E1 region: mutant E1A, mutant E1B, their transcriptional control by cancer-specific promoters, or all of the above [67].