A newly published study that takes advantage of the gene-editing technique known as CRISPR has found that at least some of those DNA strings are essential to keep healthy cells growing and block the growth of tumor cells.
https://www.geekwire.com/2020/scientists-link-mysteriously-unchanged-snippets-dna-cell-growth-tumor-suppression/
https://www.geekwire.com/2020/scientists-link-mysteriously-unchanged-snippets-dna-cell-growth-tumor-suppression/