BIRC5 and endometriosis: Recently, a systematic review that summarized the findings from 21 studies and 1263 women with endometriosis reported that survivin (gene and/or protein) expression is increased in endometriosis, regardless of the methodology used (real-time reverse transcription polymerase chain reaction (RT-PCR), quantitative PCR (RT-qPCR), immunohistochemistry, Western blot, or enzyme-linked immunosorbent assay (ELISA)), sample studied (endometrium or blood), the phenotype of the endometriosis (superficial, ovarian, and deep) or morphology of the endometriotic lesions (pigmented or non-pigmented) [43].