Evaluation of anaplastic lymphoma kinase expression in nonsmall cell lung cancer; a tissue microarray analysis

The oncogenic form of anaplastic lymphoma kinase (ALK) gene is an attractive candidate marker for diagnostic and therapeutic purposes in several malignancies, including nonsmall cell lung cancer (NSCLC). This study aimed to examine the expression levels and clinical significance of ALK in a series of NSCLC tumors.We retrospectively reviewed 140 samples of NSCLC, including 64 (46%) squamous cell carcinoma (SCC), 62 (44%) adenocarcinoma (ADC), and 14 (10%) large cell carcinoma (LCC) for expression of ALK using immunohistochemistry; and immunostaining patterns were correlated with clinicopathological parameters.Expression of ALK was significantly different between SCC with ADC (P < 0.001) and LCC samples (P < 0.001). The highest level of ALK expression was found in ADC cases with poor differentiation and high nuclear grade (P = 0.005 and P = 0.005, respectively). Furthermore, high level of ALK expression was more often observed in ADC cases with poor prognosis features (P = 0.013).These findings suggested that ALK can be considered as a promising target in the targeted therapy in patients with lung ADC.