Securin is a multifunctional protein with 202 amino acids encoded by a gene located on chromosome 5 (5q35.1), which is also called pituitary tumor transforming gene-1 and comprises 4 introns and 5 exons.[1,2] Securin is normally expressed in tissues with high proliferative activity, including the spleen, thymus gland, and testis, whereas it is rarely expressed in differentiated mature tissues.[3] Securin is a multifunctional protein that is involved in a broad spectrum of cellular physiological activities. This evidence concerns the gene PTTG1 and pituitary tumor.