We recently reported on the over-expression of a new gene, colonic and hepatic tumor over-expressed gene (ch-TOG) in human hepatomas and colonic tumors. Although ubiquitous in healthy tissues, its expression was found to be particularly elevated in the brain. In the present study, we demonstrate the expression of ch-TOG mRNA in human brain tumors as well as in numerous areas of healthy human and baboon brain. This expression was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), Northern blotting, RNAse protection assays and in situ hybridization. An interesting feature is the demonstration that, although ubiquitous in the brain, the ch-TOG gene is highly expressed in the Purkinje cell bodies of the human cerebellum.