Objective To explore the expression of insulin-like growth factor 1 receptor (IGF1R) in the gastrointestinal stromal tumor (GIST) and its clinical significance.

Methods Clinical data of 134 GIST patients underwent operations at the Department of General Surgery at Zhongshan Hospital, Fudan University between January 2008 and January 2014 were retrospectively analyzed, including IM resistant group (n=26) and non-resistant group (n=108). The clinicopathological data were collected and immunohistochemical analysis was performed based on tissue microarray to estimate the expression of IGF1R. Pearson χ² test was used to analyze the difference in IGF1R protein expression among groups with different clinicopathological characteristics. Survival curves were estimated using the Kaplan-Meier method and were compared using the log-rank test.

Results There were no significant differences in gender, age, tumor size, primary site, mitotic phase, mutation gene and NIH risk classification between IGF1R high expression group and low expression group. The expression rate of IGF1R protein in IM-resistant GIST tissues was 73.08%, and that in non-resistant tissues was 41.67%. The difference between the two groups was statistically significant (χ²=8.286, P=0.004). Univariate survival analysis of 26 cases with IM resistance showed that patients with high IGF1R expression had a significantly lower OS than those with low IGF1R expression (35.3 vs 71.3 months, P= 0.04).

Conclusions High expression of IGF1R may be involved in the mechanism of IM resistance in GIST and can serve as an indicator of poor prognosis in IM resistant cases.