Transcribed-ultraconserved regions (T-UCRs) are long non-coding RNAs (lncRNA) 
encoded by a subset of long ultraconserved stretches in the human genome. Recent 
studies revealed that the expression of several T-UCRs is altered in cancer and 
growing evidences underline the importance of T-UCRs in oncogenesis, offering 
also potential new strategies for diagnosis and prognosis. We found that 
overexpression of one specific T-UCRs named uc.63 is associated with bad outcome 
in luminal A subtype of breast cancer patients. uc.63 is localized in the third 
intron of exportin-1 gene (XPO1) and is transcribed in the same orientation of 
its host gene. Interestingly, silencing of uc.63 induces apoptosis in vitro. 
However, silencing of host gene XPO1 does not cause the same effect suggesting 
that the transcription of uc.63 is independent of XPO1. Our results reveal an 
important role of uc.63 in promoting breast cancer cells survival and offer the 
prospect to identify a signature associated with poor prognosis.