BIRC5 and pituitary tumor: We found no difference in survivin variant expression between large and small pituitary tumors (survivin, P = 0.5985; ∆Ex3, P = 0.6935; 2β, P = 0.6303) nor between functional and non-functional ones (survivin, P = 0.6181; ∆Ex3, P = 0.3334; 2β, P = 0.4878).