Expressions of Insulin-Like Growth Factor Receptor-1 and Insulin-Like Growth Factor Binding Protein 3 in Advanced Non-Small-Cell Lung Cancer

The insulin-like growth factor (IGF) pathway plays an important role in tumor progression. We examined immunohistochemical expression of both IGF receptor-1 (IGF-1R) and IGF binding protein 3 in 68 patients with advanced non-small-cell lung cancer and found that IGF-1R expression was significantly more frequent in squamous cell carcinoma (100%) than in adenocarcinoma (44%) (P < .001). IGF-1R antibody may be useful in the pathologic diagnosis in non-small-cell lung cancer. Background: The insulin-like growth factor (IGF) pathway plays an important role in cell proliferation, differentiation, and apoptosis, and IGF induces those effects mainly through IGF receptor-1 (IGF-1R). The activities of IGF are strictly regulated by a family of IGF binding proteins (IGFBP), especially IGFBP3, a major serum carrier protein for IGF. Patients and Methods: Between January 2006 and February 2009, in our hospital, 191 patients were histologically diagnosed as having non-small-cell lung cancer (NSCLC), and 74 patients were treated by chemotherapy alone. We examined immunohistochemical expression of both IGF-1R and IGFBP3 in 68 patients who were definitively diagnosed as having adenocarcinoma or squamous cell carcinoma among the 74 patients. Results: The clinical characteristics of the included patients were as follows: median age was 68 years (range, 29-86 years); men vs. women, 40 vs. 28; stage III vs. IV, 18 vs. 50; performance status 0-1 vs. 2-4, 58 vs. 10; smoker vs. non-smoker, 44 vs. 24; and squamous cell carcinoma vs. adenocarcinoma, 13 vs. 55. Expression of IGF-1R and IGFBP3 was observed in 37 (54%) and 11 patients (16%), respectively. IGF-1R expression was detected more frequently in patients with squamous cell carcinoma (100%) than in patients with adenocarcinoma (44%) (P < .001), although IGFBP3 expression was not significantly associated with any clinical variables. Among all factors, including IGF-1R and IGFBP3 expression, IGF-1R was significantly associated with response to chemotherapy (P = .028) and performance status was significantly associated with overall survival (P < .001). Conclusions: High sensitivity of IGF-1R to squamous cell carcinoma (100%) in this study and another study encourages the use of IGF-1R antibody in the pathologic diagnosis between squamous cell and non-squamous cell carcinoma when using small biopsy specimens.