|bone marrow with acute myeloid leukemia
(credit: Vashi Donsk; Wikimedia Commons)
“So doc, what’s my prognosis?”
It’s the question foremost on the minds of people who have been diagnosed with cancer. Yet giving a specific answer to an individual patient can be a challenge for cancer doctors. As the National Cancer Institute states on their website:
Because survival statistics are based on large groups of people, they cannot be used to predict exactly what will happen to an individual patient. No two patients are entirely alike, and their treatment and responses to treatment can vary greatly.
In recent years with the emergence of personalized medicine, the analysis of genetic mutations in the cancer cells of individual patients has helped more clearly define disease categories. Now, rather than inspecting mutations, a New York research team reports this month in the Journal of Clinical Investigation that comparing the pattern of chemical tags on DNA within healthy blood stem cells vs. cancerous cells can robustly predict how well an individual with acute myeloid leukemia (AML) may respond to chemotherapy.
As co-senior author Ulrich Steidl, MD, PhD, said in an Oncology Nurse Advisor article,
AML is a disease in which fewer than 30% of patients are cured. Ideally, we would like to increase that cure rate. But in the meantime, it would help if we could identify who won’t benefit from standard treatment, so we can spare them the debilitating effects of chemotherapy and get them into clinical trials for experimental therapies that might be more effective.
In a healthy individual, changes in the pattern of chemical tagging of the blood stem cells’ DNA – a process called methylation – plays a key role in determining which stem cells are transformed into mature cells of the blood system. In AML, the methylation pattern is disturbed and fewer stem cells fully mature into the various blood cells. Instead the blood stem cells make too many pre-white blood cells that are useless for fighting infection and in process crowd out critical red blood cells and platelets.
Steidl’s team analyzed the methylation pattern in the cancerous white bloods cells of nearly 700 AML patients as well as in blood stem cells of a handful of healthy people. They were able to develop a scoring method that showed those AML patients whose cancer cells had a methylation signature that more closely resembled the signatures of healthy blood stem cells, were predicted to live longer. Steidl concluded that their methylation signature test “was clearly superior to similar tests that have been used. “
Although the stem cells studied in this report won’t lead directly to new treatments, they provide a path to more specific answers that are so critical to people and their loved ones who face scary choices in their fight against cancer.
For information about CIRM-funding of stem cell-based leukemia projects, visit our leukemia fact sheet.