Read the paper at https://www.nature.com/articles/s41586-019-1198-z
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This deadly disease can evolve and change its characteristics in response to therapeutic attack.
The ability of cancer to evolve is fueled by constant changes – mutations – to its genetic code, incurred in individual cells and leading to enormous diversity within each cancer.
Thus, in each patient, our therapies are forced to deal with thousands of variants of the cancer rather than just one entity.
But there is more. Cancer cells evolve not only genetically through changes in their DNA, but also through lesser-known epigenetic changes.
Epigenetic changes are a second code that is added to the genetic code. Through modifications to the DNA or the surrounding proteins, epigenetics help control which genes are switched “on” and which are switched “off” in a cell, like a light switch. They essentially instruct the cell how to use its genome.
Therefore, to understand how tumors evolve, diversify and adapt to treatment, we need to measure not only genetic mutations but also epigenetic changes.
Researchers at Weill Cornell Medicine, New York Genome Center and the Broad Institute have developed a technology to track epigenetic changes at the level of single cancer cells. They found that cells from patients with a form of blood cancer, chronic lymphocytic leukemia, evolve and diversify through a high rate of epigenetic changes. Thus, every cell in the cancer is different resulting in a great variety of epigenetic patterns among the cancer cells.
This epigenetic information, like genetic information, serves as a heritable mark that enabled the team to trace the lineage history of each cell back to its cancerous origin and show how it had evolved in the course of the disease. Finally, they show that the lineage history directly impacts why some cells but not others respond to targeted therapy.
This technology is an additional step toward a better understanding of the factors triggering cancer evolution at a cellular level. This will enable us to investigate how different cancers affect both the genetic and epigenetic code of cells and become such a serious threat to the body.