The survivin circuitries. Survivin is a universal tumor-associated molecule that intersects multiple signaling circuits of tumor cell maintenance. These include mitotic progression via microtubule-kinetochore attachment and bipolar spindle formation, preservation of endothelial cell viability during angiogenesis, and suppression of tumor cell apoptosis. Survivin is also intercalated in p53-dependent signaling as one of the genes repressed by wild type p53, and promotes tumor cell adaptation via its association with the stress response molecular chaperone, Hsp90. Because of its crossroads functions, survivin provides a hotly pursued target for multiple approaches of rational cancer therapy. For details, see the article by 478 in this issue.