Immunhistochemical analysis of PTTG. Exemplary PTTG staining of a primary tumor of a patient (pT1N0M0), who did not develop a tumor recurrence within the observation period (a). Staining of a primary tumor of a patient (pT1N0M0) who developed a tumor recurrence 24 months after primary tumor resection (c). (e) PTTG staining in the tumor recurrence of the same patient. (b, d and f) corresponding control sections after IgG staining.