Despite decades of research and impressive strides in driving down mortality from leukemia, two simple facts remain: Not much is known about a cause, and cancers of the blood are notorious for their ability to repel chemotherapy.
"Leukemia is all about cells that got the wrong signals," said Dr. Arlene Redner, associate chief of oncology at Schneider Children's Hospital in New Hyde Park. "Instead of growing and maturing, they suffer from arrested development and crowd the normal cells out of the bone marrow."
An estimated 245,225 people in the United States are living with, or are in remission from, leukemia. An estimated 44,790 new U.S. cases are expected to have been diagnosed this year.
The public face of leukemia is often that of a child, such as 6-year-old Julianna Buttner of Farmingville, for whom more than 2,600 lined up last weekend to see if they could be bone-marrow donors. In reality, blood cancers are diseases of aging. The median age of people with leukemia is 66. The cancer strikes 10 times more adults than children.
Two forms of leukemia occur in childhood: ALL, acute lymphocytic leukemia; and AML, acute myelogenous leukemia. An estimated 80 percent of pediatric leukemias are ALL, Redner said, and 20 percent are AML. Buttner has ALL.
For adults, the incidence is reversed: 80 percent of cases are AML, and 20 percent are ALL.
ALL has one of the highest cure rates for any form of cancer affecting children. But current treatments - which mostly rely on a combination of chemotherapeutic drugs - do not always work long-term.
"Despite the fact that we celebrate the [successful] outcomes for most children with ALL, 20 percent of these patients relapse," said Dr. William Carroll, director of the cancer institute at NYU's Langone Medical Center in Manhattan.
Relapses are also common in AML, which has numerous subtypes. Some lead to a rapid episode of drug resistance. "Some children overexpress certain genes," Carroll said of strands of DNA that bear the blueprint for drug resistance.
When remissions cannot be sustained, doctors ramp up to the next step - a bone-marrow transplant, preferably from a closely matched, related donor. Bone marrow is the spongy tissue of the skeletal system. It harbors stem cells, the source from which all blood cells emerge. An infusion of healthy stem cells can result in a cancer-free blood supply.
Another source can be banked umbilical cord blood, which is rich in embryonic stem cells. Cord blood may ultimately help patients who cannot find matches in their families or communities, said Deborah Banker, a vice president at the Leukemia and Lymphoma Society's headquarters in Mamaroneck.
With adult stem cells, she said, doctors must match eight markers between donor and recipient; with embryonic cells that number is cut in half. But cord blood is expensive and in short supply.
Sometimes a wide net must be cast to find a donor.
Alex Mele, a 15-year-old leukemia patient from Coram, has had three donor drives. But so far no luck.
Alex's father, Lou, said specific groups of people may hold the key. "What the doctors tell me is that somebody of a Mediterranean background might give him better odds," Lou Mele said. "But I'll take any anybody. I'll take somebody from Oompah Oompah land if they're a match."