Prognostic significance of pituitary tumour-transforming gene-binding factor (PBF) expression in papillary thyroid carcinoma

Background Pituitary tumour-transforming gene (PTTG)-binding factor (PBF), originally known as PTTG1 interacting protein (PTTG1IP), has been found to be significantly increased in well-differentiated thyroid cancer and independently associated with early tumour recurrence. Objective To assess the prognostic significance of PBF expression in a large cohort of papillary thyroid carcinoma (PTC) patients with a long-term follow-up. Design and patients Retrospective analysis of PBF expression in PTC cases at different stages and correlate it with various clinicopathological parameters and patient survival. Subjects included 153 patients who received a thyroid operation for PTC at Chang Gung Memorial Hospital between 1991 and 2000. All patients had a complete follow-up till the end of 2010. Measurements Immunohistochemical study for PBF expression on tissue sections from tumour specimens. Bond automated machine (Leica Microsystems, Germany) with a polyclonal rabbit anti-PBF antibody (LifeSpan BioSciences, LS-C118942, Seattle, WA, USA) was used. SPSS 13.0 for Windows (SPSS Inc, Chicago, IL, USA) was used for all statistical analyses. Results High PBF expression was significantly correlated with age (P = 0·0298), distant metastases at diagnosis (P = 0·0139), tumour multicentricity (P = 0·0035), TNM stage (P = 0·0103), locoregional recurrence (P = 0·0410) and disease-specific mortality (P = 0·0064). The expression level of PBF was significantly correlated with disease-specific survival (P = 0·0065). Cox regression analysis showed that age, tumour size and PBF expression were independent prognostic indicators (P = 0·0097, P = 0·0021 and P = 0·0179). Conclusion PBF expression may be a promising biomarker for prognostic and therapeutic purpose. More large-scale studies are needed to clarify its potential usefulness.