Insulin-like growth factor-1 receptor (IGF1R) plays a key role in the initiation and progression of
breast cancer. However, its prognostic relevance to
breast cancer patients has long been a matter of debate. In a series of 325 primary invasive
breast cancer patients, we performed a comprehensive analysis of IGF1R at the levels of gene copy number,
mRNA expression and
protein expression. The relationship between the IGF1R status and the clinicopathological characteristics and prognosis was evaluated. IGF1R
mRNA levels not only correlated with
protein expression, but also were significantly associated with several clinicopathological parameters and prognosis. Patients with low nuclear grade, negative axillary lymph nodes, positive
hormone receptor, negative Her2, negative Ki67, and
luminal subtype
tumors showed higher expression levels of IGF1R
mRNA, which was shown to be a significant univariate parameter for both relapse-free survival and
breast cancer-specific survival (BCSS) as well as a significant multivariate parameter for BCSS. IGF1R
protein expression showed an association with a prolonged BCSS in univariate analysis. In contrast, IGF1R gene copy number was not correlated with
mRNA and
protein expression, and harbored no prognostic value. When studied in the
luminal tumor subtype groups, IGF1R
mRNA level was still significantly associated with a better BCSS. Overall, our data indicated a correlation between IGF1R
mRNA expression and
protein expression in primary
breast cancer. In particular, IGF1R
mRNA expression appeared to be a good prognostic marker both in the entire cohort and in the
luminal subtype group. These data may serve as background information for IGF1R-targeted
therapy.