Expressions of insulin-like growth factor receptor-1 and insulin-like growth factor binding protein 3 in advanced 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.