Expression of Insulin Receptor and c-MET Is Associated with Clinicopathologic Characteristics and Molecular Subtypes in Premenopausal Breast Cancer Patients

Receptor Tyrosine Kinases (RTKs) represent a class of transmembrane receptors known to play an important role in cancer development and progression. In this study, the expression of insulin receptor (IR) and the hepatocyte growth factor receptor (c-MET) was examined in breast cancer patients. Immunohistochemistry for IR and c-MET was performed on 71 cases of invasive breast cancer and expression scores were correlated with clinicopathologic characteristics and molecular subtypes and further stratified based on a menopausal status. Expression of IR was significantly associated with the tumor grade (p = 0.017) and estrogen receptor (ER) expression (p = 0.015). There was a significant positive correlation between IR and c-MET expression scores (rho = 0.458, p < 0.001). Among premenopausal cases, IR scores were significantly higher in patients with grade I/II disease (p = 0.025), ER-positive (p = 0.030), and progesterone receptor (PR)-positive carcinoma (p = 0.015). c-MET expression scores were significantly higher among premenopausal patients with ER-positive (p = 0.007) and PR-positive carcinoma (p = 0.024). IR expression scores were significantly different among molecular subtypes for all patients (p = 0.006) and among premenopausal cases (p = 0.035). c-MET expression was statistically different among molecular subtypes for premenopausal patients (p = 0.019). Survival analysis revealed that the expression status of IR and c-MET was not associated with overall survival. Our findings support a favorable prognostic value for IR and c-MET expression in premenopausal breast cancer patients.