TMEFF1 and brain tumors.

TMEFF1 is a novel transmembrane protein, containing two follisatin domains and an epidermal growth factor-like region. These structural domains suggest a role for TMEFF1 in growth factor signaling. TMEFF1 fused to enhanced green fluorescent protein revealed that TMEFF1 is expressed on the cell membrane. Northern analysis of normal human tissue showed that TMEFF1 is predominantly expressed in the brain. Study of cancer cell lines from different tissues including the brain, demonstrated moderate to low levels of TMEFF1 in most of these transformed cell lines. Furthermore, quantitative real-time RT-PCR analysis of 54 brain tumors showed that most of these tumors (96%) had lower levels of TMEFF1 expression than normal brain tissue. Interestingly, ectopic expression of TMEFF1 in brain cancer cells resulted in their growth inhibition. These data suggest that TMEFF1 may behave as a tumor suppressor gene in brain cancers.