1. ¹Division of Surgical Pathology, Department of Surgery, University of Pisa, Pisa 56100, Italy
2. ²Scuola Normale Superiore, INFN, Section of Pisa, Pisa 56100, Italy
3. ³Department of Cardio-Thoracic Surgery, University of Pisa, Pisa 56100, Italy
4. ⁴Dipartimento di Biologia e Patologia Cellulare e Molecolare, University 'Federico II', Naples 80131, Italy
5. ⁵Department of Oncology, Transplants and New Technologies in Medicine, University of Pisa, Pisa 56100, Italy

Correspondence: Professor G Fontanini, E-mail: g.fontanini@med.unipi.it

Received 2 February 2005; Revised 6 June 2005; Accepted 20 June 2005; Published online 9 August 2005.

Abstract

Osteopontin (OPN) is a multifunctional protein, which has recently been shown to be linked to tumorigenesis, progression and metastasis in different malignancies. Since non-small-cell lung cancer (NSCLC)'s prognosis remains bad, with few predictors of outcome, the purpose of this study was to evaluate if OPN might be involved in NSCLC's biology and therefore represent a prognostic marker and a target for new therapeutic trials. Immunohistochemistry was used to detect OPN expression, evaluated as percentage of neoplastic cells with cytoplasmic immunoreactivity, in a wide cohort of patients with stage I NSCLC (136 cases). The median value of this series (20% of positive cells) was used as the cutoff value to distinguish tumours with low (<20%) from tumours with high (20%) OPN expression. A statistically significant correlation between high levels of OPN and shorter overall (P=0.034) and disease-free (P=0.011) survival in our patients was shown. Our results support the hypothesis that high OPN expression is a significantly unfavourable prognostic factor for the survival of patients with stage I NSCLC. This conclusion has notable importance in terms of the biological characterization of early-stage tumours and therapeutic opportunities.