Expression of HOXC9 and E2F2 are up-regulated in CD133+ cells isolated from human astrocytomas and associate with transformation of human astrocytes

Comparative analysis of cancer stem cells with their neoplastic and non-neoplastic counterparts should help better understand the underlying molecular events leading to transformation and tumor dissemination. Here, we report a molecular signature comprised by genes with exclusive aberrant expression in CD133+ cells, a reported subpopulation of tumorigenic stem-like cells, isolated from human glioblastomas. Microarrays covering 55,000 transcripts were used to compare gene expression profiles in purified subpopulations of CD133+ and CD133− GBM cells. Sixteen genes, many of which not previously associated with astrocytomas, were found aberrantly expressed in CD133+ cells, but not in CD133−, when compared with corresponding non-neoplastic controls. Up-regulation of two of such genes, E2F2 and HOXC9, was detected in a set of 54 astrocytomas of different grades and significantly associated with malignancy. Due to their distinctive expression in CD133+ cells, the use of E2F2 and HOXC9 as therapeutic targets for tumor eradication is suggested.