Clinical Significance of IGF1R Expression in Non–Small-Cell Lung Cancer

BackgroundThe purpose of the current study was to clarify the clinical role of insulin-like growth factor receptor-1 (IGF1R) in NSCLC.Patients and MethodsTumor specimens were collected from 285 patients who underwent complete resection for adenocarcinoma (AD, n = 182), squamous cell carcinoma (SCC, n = 77), and other histologic types of cancer (n = 26) of the lung. The expression of IGF1R and Ki-67 was evaluated by immunohistochemical (IHC) analysis.ResultsPositive expression of IGF1R was detected in 87 (30.5%) of 285 cases, of which 43 (23.6%) of 182 cases were AD, 36 (46.8%) of 77 cases were SCC, and 8 (30.8%) of 26 cases were other histologic types (SCC vs. AD, p < .001; SCC vs. non-SCC, p < .001). Positive IGF1R expression was also identified in 20 (44.4%) and 67 (27.9%) of the patients with and without recurrence, respectively (p = .027). Multivariate logistic regression models indicated that positive staining for IGF1R expression was an independent factor in AD associated with tumor recurrence (p = .040) but not in NSCLC, SCC, and other types of cancer. A positive IGF1R expression tended to demonstrate a poor disease-free survival (DFS) in NSCLC according to the Kaplan-Meier DFS curves (p = .053). The tumors showing a positive expression of IGF1R were observed more frequently in tumors with a positive expression of Ki-67 than in the tumors with a negative expression of Ki-67 (p = .010).ConclusionIGF1R expression was associated with reduced DFS correlating with postoperative recurrence. In addition, a significant relationship was also observed between IGF1R and Ki-67 expression in NSCLC. However, in subgroup analysis, a significant correlation was not observed. IGF1R expression predicts postoperative recurrence in patients with AD, but not in those with non-AD of NSCLC.