Identification of cancer stem cells in dog glioblastoma.

There is increasing evidence in some malignancies that the tumor clone is heterogeneous in regard to proliferation and differentiation. The cancer stem cell hypothesis implies that not all the cells in the tumor have the same capacity to proliferate and maintain the growth of the tumor. Only a relatively small fraction of cells in the tumor, termed cancer stem cells (CSCs), possess the ability to proliferate and self-renew extensively. In the past decade, several groups have reported the existence of a CSC population in different human brain tumors from both children and adults. We report here the identification of a CSC population from a Boxer dog with glioblastoma multiforme (GBM) that possesses a great capacity for proliferation, self-renewal, and differentiation. This cloned cell line is aneuploid, forms neurospheres in culture, possesses CSC markers, and reproduces the original dog GBM when inoculated into the nude mouse brain.