Cancer cells: Shown here are bone marrow cells collected from a leukemia patient. Scientists searched for cancer-related mutations by comparing the DNA in these cells and the patient’s healthy skin cells.
Comparing healthy cells and cancer cells reveals genetic missteps in cancer
Source: “DNA sequencing of a cytogenetically normal acute myeloid leukaemia genome”
Elaine Mardis et al.
Nature 456: 66-72
Results: Scientists from Washington University in St. Louis identified 10 genetic mutations found in the DNA of cancer cells but not in healthy cells. Both sets of cells were collected from a patient who had leukemia.
Why it matters: Previous studies that analyzed tumor DNA focused on genes thought to play a role in cancer, thus neglecting much of the genome. The new study provides an unbiased search through the entire genome, identifying genetic variants that scientists might never have noticed. The findings provide new targets for further research and drug development.
Methods: The scientists used a new sequencing technology, from San Diego-based Illumina, that is much cheaper than traditional methods. For the first time, they created full-genome sequences of both cancerous and healthy cells taken from the same person, a woman who died of acute myelogenous leukemia. By comparing the two sequences, they identified specific changes found only in the cancer cells.
Next steps: The scientists have almost finished sequencing the genome of a second patient. Because this patient is still alive and in remission, the genetic variants identified in his cancer cells may reveal clues to what makes treatment successful. The researchers are also planning to sequence genomes from different types of solid tumors.