Scientists studying cancer devote a great deal of attention to individual genes, boosting or suppressing their activity in the laboratory to tease out their respective roles in tumor formation. But a group in the Children's Hospital Informatics Program (CHIP) has been studying cancer in a more holistic way. By systematically comparing the genetic profiles of a broad range of cancers to genetic profiles seen during physiologic development, they've sorted cancers into three groups that exist along a continuum, reporting their findings in the July 2008 issue of Genome Biology.
"We're going for the big picture, trying to capture a tumor's macroscopic properties," says Kamila Naxerova, the report's first author and a graduate student working with CHIP director Isaac Kohane, MD, PhD.
They've found that one group of cancers has stem-cell-like and proliferative expression patterns similar to those that occur during early development, and tend to grow aggressively. The second group, with more indolent cancers, expresses many genes linked to inflammation, a pattern seen during late embryonic development. The third group falls somewhere in the middle.
Naxerova and colleagues were surprised at some of the cancers that wound up in the same category. For instance, both the lung cancer adenocarcinoma and Wilms' tumor, a type of pediatric kidney cancer, landed in the early developmental group. "It's not what I would have expected," says Naxerova, "since these tumors arise under very different circumstances and are associated with different DNA alterations."
The finding suggests that, as unlikely as it seems, drugs effective against lung cancer might work against kidney tumors in children. "Grouping cancers in this developmental context could provide a different therapeutic strategy," Naxerova says.