Determination of SGK1 mRNA in non-small cell lung cancer samples underlines high expression in squamous cell carcinomas

By means of immunohistochemistry and quantitative real-time PCR, we determined SGK1 protein and mRNA expression in a cohort of 66 formalin-fixed, paraffin-embedded NSCLC surgical samples. All samples belonged to patients with a well-documented clinical history.mRNA expression was significantly higher in squamous cell carcinomas, and correlated with several clinical prognostic indicators, being elevated in high-grade tumors and in tumors with bigger size and worse clinical stage. No correlation was found between SGK1 protein expression and these clinical parameters.This explorative analysis of SGK1 expression in NSCLC samples highlights the potential role of this factor in NSCLC patients' prognosis. Moreover, the higher expression in the squamous cell carcinoma subtype opens new therapeutic possibilities in this NSCLC subtype by designing specific kinase inhibitors.Lung cancer represents the foremost cause of cancer death, at least in Western countries [1-3]. From a clinical point of view, lung cancer is classified as "small cell lung cancer" (SCLC) and "non-small cell lung cancer" (NSCLC), the form by far most frequent (about 85% of the total cases). NSCLCs are histopathologically subdivided into adenocarcinoma, squamous cell carcinoma and large cell carcinoma [1]. Recently, this NSCLC subclassification has been shown to reflect also specific epidemiological as well as biological behaviors, which can be epitomized in a higher incidence in never-smokers and in women of the adenocarcinomatous subtype [4-7] and in its higher sensitivity to EGFR tyrosine kinase inhibitors [8].In NSCLC, a major role is attributed to the membrane-bound tyrosine kinase receptors, mainly EGFR, which in their active, phosphorylated form generate a cascade of biological effects which strongly favor several biological processes, as cell proliferation, neo-angiogenesis and invasive capability [9]. Interestingly, also insulin and insulin receptor have been recently involved in lung epithelial ce