Prognostic impact of insulin receptor expression on survival of patients with nonsmall cell lung cancer

BACKGROUND

The purpose of this study was to characterize insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF-1R) expression in patients with nonsmall cell lung cancer (NSCLC).

METHODS

A total of 459 patients who underwent curative resection of NSCLC were studied (median follow-up duration, 4.01 years). Expression of the IR and IGF-1R protein in tumor specimens was assessed immunohistochemically using tissue microarrays.

RESULTS

The cytoplasmic IR score was higher in patients with adenocarcinoma (ADC) than in those with squamous cell carcinoma (SCC), whereas cytoplasmic IGF-1R score was higher in patients with SCC than those with ADC. Neither IR nor IGF-1R expression was associated with sex, smoking history, or clinical stage. Patients with positive IR or IGF-1R expression levels had poor recurrence-free (RFS) (3.8 vs 3.3 years; 3.8 vs 2.0 years, respectively), but similar overall survival (OS). Patients with high expression levels of IR and IGF-1R had shorter RFS and OS compared with those with low levels of IR and/or IGF-1R expression. Finally, a multivariate analysis revealed the impact of IR, but not of IGF-1R, as an independent predictive marker of NSCLC survival: hazard ratio (HR) for OS, 1.005 (95% confidence interval [CI], 1.001-1.010], HR for RFS, 1.005 (95% CI, 1.001-1.009), when IR score was tested as a continuous variable.

CONCLUSIONS

Overexpression of IR predicts a poor survival among patients with NSCLC, especially those with SCC. These results might serve as future guidance to the clinical trials involving IR or IGR-1R targeting agents.

Summary of presentations from the 46th Annual Meeting of the American Society of Clinical Oncology (2010) focus on tumor biology and biomarkers related to lung cancer

Globally, lung cancer remains the most common cause of cancer-related death. In recent years, it has become clear that development of rational molecular targeted therapies is critical to improve the outcomes of patients with lung cancer. A better understanding of the tumor biology is crucial to achieve this goal. Several new findings in the field of tumor biology were presented at the 46th Annual Meeting of the American Society of Clinical Oncology. Novel genetic mutations were identified in pleural mesothelioma using array-based technologies. Several studies on the development and testing of new molecular diagnostic tests to detect epidermal growth factor receptor tyrosine kinase mutations and EML4-ALK (Echinoderm Microtubule-associated Protein like 4 Anaplastic Lymphoma Receptor Tyrosine Kinase) fusion gene were presented as well.