The findings advance scientists' understanding of glioblastoma, the most common and most aggressive type of primary brain tumor, accounting for 52 percent of all primary brain-tumor cases, said Inder Verma, professor in the Laboratory of Genetics at the Salk Institute in La Jolla, Calif.

The researchers sought to mimic randomly occurring mutations that lie at the heart of all tumors, and use modified viruses to bring oncogenes -- a protein-encoding gene that, when deregulated, causes cancer -- into a handful of cells in adult mice.

They found that the mouse models of human cancer could faithfully reproduce different types of tumors, but also clarify cancer stem cells' elusive nature, Verma said.

"These findings show that our cancer model will not only allow us to start understanding the biology of glioblastoma, but will also allow us to answer many questions surrounding cancer stem cells," he said.

While the work, published in the journal Nature Medicine, pertains to glioblastoma, Verma said he and his team were also using the methodology to investigate lung, pancreatic and pituitary cancers.