The insulin-like growth factor-I receptor (IGF-IR) is a member of the transmembrane tyrosine kinase family that regulates various biological processes. These processes include maintaining optimal cell growth, establishing and maintaining the transformed phenotype, tumorigenesis for several types of cells, and antiapoptosis. This study investigated the immunohistochemical expression of IGF-IR in relation with the expression of the estrogen receptor (ER), the progesteron receptor (PR), proliferative activity (Ki-67) as well as with the other conventional clinicopathlogical parameters in breast cancer.

This study was performed on paraffin sections from 64 invasive ductal breast carcinoma specimens by immunohistochemistry using rabbit polyclonal antibodies to the IGF-I receptor.

IGF-IR expression was detected in 56 (87.5%) cases. The immunohistochemical stains for the IGF-IR were scored according to a semi quantitative scoring system. IGF-IR staining was positively correlated with the ER status, but not significantly with the PR, lymph node status, tumor size, histological grade, and proliferative activity. The Ki-67 labeling index showed a significant correlation with the tumor grade and ER status.

The IGF-IR may play a role in estrogen-mediated growth and the pathogenesis of breast cancer.