Additional over expressed transcripts identified by comparative global microarray analysis using in vitro differentiated trisomic BG01V APCs include those encoding signaling molecules such as the protein phosphatase, PPP2R2B, the purinergic receptor, P2RY5, the ras homolog, RHOU, and others not previously associated with astrocytomas or astrocytic cancer stem cells. Here, RHOU is linked to astrocytoma (excluding glioblastoma).