Scientists for the first time have been able to look at the entire set of genes from a cancer patient, identifying a series of gene mutations that were never linked to the type of cancer that killed the woman.
The study, published Wednesday in the journal Nature, was conducted at Washington University in St. Louis.
The patient was a woman in her 50s who died of acute myelogenous leukemia, a cancer of blood-forming cells in the bone marrow. Using DNA sequencing, the scientists were able to map all the genes in her tumor cells and to compare them with the genes from a normal cell.
They found 10 mutated genes in the cancerous tissue apparently involved in triggering AML. Previous research had linked two of them to AML, but the rest never before had been implicated. One of the newly discovered abnormal genes blocks chemotherapy drugs from ever getting inside the cancer cells to kill them.
"We found mutations in genes that make a lot of sense when normal cells become cancer cells," said study senior author Richard K. Wilson, director of the Washington University Genome Sequencing Center, in St. Louis. The Washington team’s project marks the first time a person’s entire DNA has been sequenced and also opens the door to further research concentrating on other types of cancer than leukemia, which is expected to be performed in the near future.
"There are probably many, many ways to mutate a small number of genes to get the same result, and we're only looking at the tip of the iceberg in terms of identifying the combinations of genetic mutations that can lead to AML," Richard Wilson said in a statement. He said he hoped in twenty years or less, scientists would be able to come to perform DNA sequencing by using only a drop of blood that would be analyzed by a computer.
Researchers are now trying to identify all the genetic mutations that cause lung, brain and ovarian cancers. Scientists analyze huge quantities of genetic information from different tumor samples in an attempt to find the pathways that most patients share. Researchers are trying to identify which genetic alterations cause which cancers. The findings open the door to finding cancer before it has spread, when it can still be cured by means of surgery.
Cancer is a class of diseases in which a group of cells display uncontrolled growth, invasion, and sometimes metastasis. They grow beyond the normal limits, destroy adjacent tissues and sometimes spread to other locations in the body via lymph, or blood. Nearly all types of cancers are caused by abnormalities in the genetic material of the transformed cells.
Myelogenous leukemia is a common form of cancer that affects blood and bone marrow. The researchers chose to study this disease because it is severe and the treatment has not improved in decades. Each year in the United States, nearly 8,800 people die of AML. About 13,000 new cases of acute myelogenous leukemia are diagnosed in the United States each year.
