EWSR1 and Ewing sarcoma: Human Rpb5 also interacts with the Human TATA-binding protein (TBP)-associated factor 68 (TAFII68), an RNA/ssDNA binding protein that was originally identified for its homology to the proto-oncogenes EWS (Ewing's Sarcoma) and TLS (Translocated in Liposarcoma; another member of the EWS gene family) [48]–[50].