BIRC5 and neoplasm: Although Survivin was initially described as a ubiquitous and universally present marker of human epithelial malignancies (Ambrosini et al, 1997), such differences in the prevalence of expression may be explained by intrinsic differences in tumour biology and higher affinity of the polyclonal antibody as compared to its monoclonal counterpart (Altieri et al, 1999).