Immunohistochemical evaluation of insulin-like growth factor receptor 1 in breast cancer

Introduction/Objective Activation of insulin-like growth factor receptor (IGF-1R) results in cell transition from growth phase to synthesis phase of cell cycle. Breast cancer is categorized into prognostic and therapeutic subtypes based upon hormone receptor, estrogen receptor (ER), and progesterone receptor (PR) expression and human epidermal growth factor receptor 2 (HER-2) expression. The objective of this study was to examine the expression of IGF-1R in a specific subtype invasive breast cancer and its correlation with basic histopathological and immunohistochemical prognostic parameters. Methods Formalin-fixed paraffin-embedded tumor samples were obtained from 129 female patients with invasive breast cancer (I-Ill disease stage) with the follow-up ranging 36-108 months (average 48 months). For immunohistochemical staining, we used monoclonal antibodies for ER, PR, IGF-1R, and polyclonal antibody for HER-2. Results IGF-1R inversely correlated with tumor stage (p = 0.017), tumor grade (p = 0.001), HER-2 (p = 0.003), whereas significant positive correlation was found with multifocality/multicentricity of breast cancer (p = 0.036), ER (p = 0.001) and PR (p = 0.0001) expression. Cox-regression analysis for relapse-free survival (RFS) showed that disease stage (p = 0.039) and HER-2 (p = 0.033) were independent prognostic factors. IGF-1R did not predict clinical outcome in patients with breast cancer (p = 0.488, Kaplan-Meier test for RFS). Conclusion Patients with low stage and grade hormone-dependent breast cancer had a significantly higher IGF-1R expression than patients with triple negative or HER-2 overexpressed cancer. The present findings also highlight that IGF-1R expression in multicentric/multifocal breast cancer supports the key roles in tumor initiation.