The prognostic significance of the insulin‐like growth factor‐1 ligand and receptor expression in breast cancer tissue

BACKGROUND AND OBJECTIVES: Previous in vitro studies have suggested that IGF-1 stimulation can lead a more aggressive breast cancers and subsequent poor prognosis in breast cancer patients. We aim to how IGF-1 and IGF-1R mRNA levels in breast cancer are associated with disease-free survival (DFS) and other clinicopathological factors. METHODS: IGF-1 and IGF-1R mRNA levels were measured in breast cancer tissue from 132 patients using real-time PCR. DFS and clinicopathological information were obtained from patient case notes. RESULTS: IGF-1 and IGF-1R mRNA levels did not correlate with any clinicopathological factors. Patients who relapsed had lower IGF-1 mRNA levels in their tumour tissue compared to those who remained disease-free during the 5-year follow-up period. Patients who had ER-positive breast cancers with high IGF-1 mRNA levels had longer DFS compared to those with low IGF-1 mRNA levels. IGF-1 mRNA levels was not associated with DFS in patients with ER-negative cancers. IGF-1R mRNA levels was not associated with DFS in any subgroup analysis. Multivariate analysis showed that IGF-1 mRNA levels and histopathological grade were independent predictors of DFS. CONCLUSIONS: Breast cancer tissue IGF-1 expression is a favourable prognostic indicator and could be used in clinical setting in planning for adjuvant treatment.