Osteopontin expression profiles predict pathological and clinical outcome in breast cancer.

Abstract

BACKGROUND: Osteopontin (OPN) overexpression in breast cancer has been associated with adverse pathological and clinical outcomes. In this study, the OPN expression profiles were examined in a cohort of breast cancer patients. PATIENTS AND METHODS: RNA extraction and reverse transcription were performed on breast carcinomas (n = 127) and normal tissues (n = 33). Transcript levels were determined using real-time PCR. RESULTS: The OPN-a levels decreased with increasing TNM stage and worse clinical outcome. The OPN-b levels increased with tumour grade and Nottingham Prognostic Index (NPI) stage, were higher in patients who died of breast cancer than in those who were disease-free after 10 years and predicted disease-free survival. The OPN-c expression was associated with tumour grade and poor prognosis. Furthermore, the expression levels predicted local recurrence, disease-free survival and bone metastases. CONCLUSION: OPN expression profiles are significantly associated with tumour grade, stage and patient prognosis in breast cancer. OPN-c is likely to be of particular utility as a prognostic marker and should be included in future validation studies.