Immunoreactivity of integrin-linked kinase in primary non-small-cell lung cancer and survival after curative resection

Objective: Increased immunoreactivity of integrin-linked kinase (ILK) in the primary tumour is an adverse prognostic factor in a variety of preclinical and clinical models of human cancer. Here, we investigate the relationship between ILK immunoreactivity in primary non-small-cell lung cancer (NSCLC) and the survival after curative lung resection. Methods: Tumour specimens of 138 radically operated NSCLC patients have been retrieved from the pathology archive, mounted in tissue microarrays and immunostained against ILK. The immunoreactivity against ILK has been graded in a semi-quantitative manner (negative or 1–3 positive) by two observers blinded to any patient data, and correlated to the survival data. Results: In total, 88 of 138 tumours (64%) showed an ILK immunoreactivity, which varied significantly between various histological subtypes as it ranged from 46% (squamous cell carcinoma (SCC)) to 79% (adenocarcinoma) (p = 0.019). The 5-year cancer-related survival of ILK-positive SCC patients was at 42 ± 10% versus 72 ± 9% significantly shorter than in ILK-negative patients (p = 0.011). In addition, the recurrence-free survival (RFS) of ILK-positive SCC patients was also significantly shorter than of ILK-negative patients (38 ± 10% vs 60 ± 10%) (p = 0.005). In multivariate analysis, ILK expression was a significant prognostic factor for RFS in squamous cell carcinoma (p = 0.018), but not in adenocarcinoma or in the rare histology group. Conclusions: Primary NSCLC tumours show a variable ILK immunoreactivity, dependent on the histological subtype. In SCC, ILK immunoreactivity is a significantly adverse prognostic factor.