BACKGROUND: Transcribed ultraconserved regions (T-UCRs) are a novel class of 
noncoding RNAs that are highly conserved among the orthologous regions in most 
vertebrates. It has been reported that T-UCRs have distinct signatures in human 
cancers. We previously discovered the downregulation of T-UCR expression in 
gastric cancer (GC), indicating that T-UCRs could play an important role in GC 
biology. Uc.160+, a T-UCR reported to be downregulated in human cancer, has not 
been examined in GC.
METHODS: We analyzed the expression pattern of Uc.160+ in nonneoplastic and 
tumor tissues of the stomach by using uantitative reverse transcription 
polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH), 
specifically focusing on the mechanism of transcriptional regulation and target 
genes that are regulated by T-UCRs. We also attempted to determine the effect of 
Uc.160+ expression on biological features of GC cell lines by Western blotting.
RESULTS: On the basis of the qRT-PCR and ISH results, Uc.160+ expression in 
adenoma and GC tissues was clearly downregulated compared with that in 
nonneoplastic mucosa tissues of the stomach. Cancer-specific DNA methylation in 
the promoter region of Uc.160 was observed by bisulfite genomic DNA sequencing 
analysis. The effect of DNA methylation on Uc.160+ expression was further 
confirmed by reporter gene assay. We also revealed that Uc.160+ inhibited the 
phosphorylation of Akt by regulating phosphatase and tensin homolog (PTEN) 
expression.
CONCLUSIONS: These results indicate that Uc.160+ could possibly have a tumor 
suppressive role in GC.