Correlation of Insulin-like Growth Factor 1 Receptor Expression With Different Molecular Subtypes of Breast Cancer in the UAE

Abstract

Background: Insulin-like growth factor 1 receptor (IGF1R) activation triggers multiple signaling pathways involved in proliferation and anti-apoptosis in breast cancer (BC).

Materials and methods: Immunohistochemistry for IGF1R was performed on 50 BC cases; expression was assessed for staining intensity and localization pattern (mixed, membranous, and cytoplasmic) which was correlated to hormone receptor status.

Results: Of estrogen receptor-positive (ER⁺) cases, 97.2% were IGF1R⁺ (48.6% mixed, 43.2% membranous, and 5.4% cytoplasmic pattern) compared to ER^- cases (38.5%, 7.7% and 30.8%, respectively) (p=0.003). In progesterone receptor-positive (PR⁺) cases, 97.2% were IGF1R⁺, (47.2%, 41.7% and 8.3%, respectively) compared to PR^- ones (42.9%, 14.3% and 21.4%, respectively) (p=0.036). For human epidermal growth factor receptor 2-negative (HER2^-) cases, 88.8% were IGF1R⁺ (44.4%, 8.3% and 36.1%, respectively). All HER2⁺ cases were IGF1R⁺ (71.4%, 7.1% and 21.4%, respectively) (p=0.015). In conclusion, hormone receptor-positive HER2^- cases showed membranous and mixed IGF1R localization. However, hormone receptor-negative and HER2⁺ showed cytoplasmic or diminished IGF1R expression.

Conclusion: These luminal subtypes may benefit from targeted IGFR therapy in the future.

Keywords: Breast cancer; IGF1R; immunohistochemistry; molecular subtypes.