Survivin is an inhibitor of apoptosis protein and regulates the cell cycle in 
the G2/M phase. Survivin is expressed during embryonic and fetal development, 
selectively over-expressed in common human cancers and completely down-regulated 
in normal adult tissue. This work was aimed at studying the expression of the 
survivin homologues and their subcellular distribution in fetal and normal adult 
tissues of rat. Survivin expression was evaluated by immunohistochemistry in 
formalin-fixed, paraffin-embedded tissue sections of fetal and normal adult 
tissues of rat using the polyclonal serum SUR12A-CFI. This serum demonstrated 
intense positive survivin staining in adult kidney, ovary and oviduct, and a 
variable expression in different fetal organs, with particularly intense 
expression detected in the adrenal gland, liver, stomach, small intestine, 
colon, kidney and skin. In both fetal and adult tissues, the expression was 
predominantly cytoplasmic. It was concluded that survivin was abundantly and 
prominently expressed during fetal development in rat and that the polyclonal 
anti-human survivin antibody SUR12A-CFI is reactive with rat survivin.