Do brain tumors arise from a transformed NSC: what is the evidence?
The traditional hypothesis has been that brain tumors arise from the dedifferentiation of a mature brain cell in response to genetic alterations. This hypothesis prevailed because it was felt that the postnatal brain had no proliferation. It has also been considered for some time that brain tumors may arise from a transformation event in a resident immature brain cell. With the discovery of adult NSCs (early 1990s) (Reynolds and Weiss, 1992; Kilpatrick and Bartlett, 1993; Lois and Alvarez-Buylla, 1993), it became conceivable that a normal NSC or progenitor cell that resides in the brain may be the target for transformation leading to a brain tumor.The potential that an NSC may be transformed into a brain tumor has been considered based on the observations of tumors occurring in the brain’s putative stem cell or proliferative zones in a number of older experimental systems. The ‘subependymal plate’ or subventricular zone was suspected many years ago to contain ’embryonal rests’ that wer
