Tumor Suppressor Candidate 5 (TUSC5)

LOST1 gene was affected by a homozygous deletion of about 170 kb in a small cell lung cancer cell line. Using real-time RT-PCR, they showed that expression of LOST1 was reduced in 11 (69%) of 16 of lung cancer specimens and that significant DNA hypermethylation was observed at the 5-prime end of the LOST1 gene in 4 of 6 lung cancer cell lines with negligible LOST1 expression.

The transcript contains 2 polyadenylation signals, and the deduced 177-amino acid protein contains 2 transmembrane domains. RT-PCR of human tissues detected relatively high TUSC5 expression in heart, smooth muscle, and skeletal muscle, with lower expression in adult brain, bronchus, heart, mammary gland, stomach, adrenal gland, and in fetal brain.