CTCF and infection: Furthermore, a recent study showed that infection with an oncolytic adenovirus (Ad315-E1A) or a replication-deficient recombinant adenovirus (Ad315-EGFP) significantly decreased cell viability and induced apoptosis of colon cancer cells in vitro and reduced tumor growth in a xenograft model by targeting CTCF binding sites (CCCTC) [52].