In 2006, Shideng Bao and colleagues published “Glioma Stem Cells Promote Radioresistance by Preferential Activation of the DNA Damage Response,” hereafter “Glioma Stem Cells,” in Nature. The study describes how cells within a glioblastoma, a type of fast-growing brain tumor, have a high expression of a protein called CD133, which is associated with neural stem cells. Among those cells with high expression of CD133, there exist many stem cells called glioma stem cells. In the paper, Bao and colleagues demonstrate that glioma stem cells are more resistant to radiation compared to other cells within a glioblastoma tumor, and that their resistance has to do with their ability to repair DNA. “Glioma Stem Cells” was one of the first studies to identify the role of glioma stem cells in resistance to radiation and laid the framework for future studies that investigated their role in tumor progression and recurrence as well as novel treatments targeting those cells.

In 2003, Sheila Singh and colleagues published “Identification of a Cancer Stem Cell in Human Brain Tumors” in the journal Cancer Research. The study examines a small population of cells within brain cancers that have abilities similar to those of neural stem cells and can maintain the growth of a brain tumor. The researchers identified the brain cancer stem cells by looking at the expression of proteins CD133 and nestin, which are usually present in neural stem cells. In addition, they characterized brain cancer stem cells as having the ability to quickly proliferate and self-renew, form tumor spheres, as well as differentiate in a manner that resembles characteristics of the original brain tumor from which those cells originated. “Identification of a Cancer Stem Cell in Human Brain Tumors” was one of the first studies to identify cancer stem cells in brain cancer and laid the framework for future research investigating the role of brain cancer stem cells in response to treatment, as well as the recurrence of a tumor after treatment.