By using flies, scientists at The Johns Hopkins University have linked mutations in specific genes to about 200 tiny cells whose unchecked growth leads to fatal brain tumors. The success of their experiments, they say, is proving the insect's value as a model for cancer research.
Biology professor Allen Shearn has used flies for years to study how the functions of specific genes integrate with a variety of developmental processes. But these recent findings proved particularly noteworthy as researchers in his lab have started mapping pathways that stimulate cancerous growth, beginning in genetic material and culminating in deadly tumors.
Perhaps even more noteworthy, he says, is that one of the genes in the most recent fly experiments corresponds to a human gene that has been implicated in the spread of cancer. In the past, most cancer research has been conducted in mammals.
"It turns out that some people have known that there are mutations in flies that cause specific tumors, but they really hadn't been studied much," Shearn says. "In humans, it's difficult because people get tumors, which have certain properties, but you really don't know if they're from the same or different causes.
"In flies, however, we can know what the causes are, more or less. We know the mutations and we know they cause tumors in the brain. In the case of the three genes we examined, the tumors invaded the same host tissues with the same frequency and the tumors grew at the same speed. Essentially, we found that three different genes were using the same pathway. It was remarkable."
One property in particular makes the fly an excellent source for the study of cancer, Shearn says: The metastatic process is extremely fast. In Shearn's lab, researchers discovered that they could transplant tumorous brain tissue into the abdomen of a female fly and recover huge brain tumors within two weeks.