It's been notoriously difficult to develop medicines for Alzheimer's disease, the sixth leading cause of death in the United States. Each year, it seems, pharmaceutical companies release data from studies of promising drug candidates that merit only a collective sigh of disappointment.
In search of fresh ideas, researchers have begun to borrow a phrase or two from the more familiar language of cancer treatment.
Some scientists are studying precision medicine, or personalized medicine, which is routinely used to treat breast and colon cancers. Other researchers are focusing on immunotherapy, an effective form of medicine for skin, lung, kidney, bladder and other cancers.
This translation of the cancer-fighting vocabulary to Alzheimer's disease, though, is not always simple.
"In precision medicine, in order to apply the most effective treatment possible, doctors select treatments based on the patient's genetic profile," explained Dr. Christiane Reitz
, assistant professor of neurology and epidemiology at the Columbia University Department of Neurology.
The first step when applying precision medicine to Alzheimer's disease is to learn "as many of the genetic variants as possible" that cause this common form of dementia, said Reitz, whose research focuses on identifying both genetic and non-genetic factors that contribute to changes in the brain.
"There are diseases that are caused by only one gene or very few genes," she said. Huntington's disease, a classic example, is caused by a single gene mutation: If you have the mutation, you will develop the disease.
Late-onset Alzheimer's, though, is nothing like Huntington's or even most diseases.
"There are likely more than a hundred genes involved in Alzheimer's," Reitz said. "We know some of them but not all. We need to identify the remaining ones."
In a recently published study
, Reitz noted that scientists have mapped "27 susceptibility loci" for Alzheimer's disease: regions on the chromosome that are most likely to mutate and thereby contribute to the risk of that disease.