Repeat cDNA can be integrated into the genome in a way that helps the cancer cell survive and grow. The cDNA acts like a bandage, helping replace damaged DNA and allowing the cell to thrive even when it is facing replication stress from the rapid divisions that are characteristic of cancer.
A second molecule called LINE1 endonuclease also provides a bandage-like effect. By repairing damaged parts of cDNA, it allows the cell to continue proliferating.