BIRC5 and rheumatoid arthritis: In the present study, we evaluated the expression pattern of survivin and its splice variants in RA synovial tissues and compared them to osteoarthritis (OA) tissues, and examined whether survivin might be involved in pathological RA-FLS proliferation using small interfering RNA (siRNA)-mediated knockdown and in vitro-transcribed (IVT) mRNA transfection.