[Non-small cell lung cancer. New biomarkers for diagnostics and therapy]

Abstract

Although advances in targeted therapies have recently been achieved, lung cancer remains a major health burden worldwide. It is therefore pivotal to investigate the biology of lung cancers in order to design new therapeutic strategies. To address this a multi-antibody assay has been developed for the classification of non-small cell lung cancer (NSCLC). Using this assay the pathologist is able to reliably subtype NSCLC into adenocarcinoma, squamous cell carcinoma, large cell neuroendocrine carcinoma (LCNEC) and NSCLC not otherwise specified (NOS) large cell carcinoma, as required by the new World Health Organization (WHO) classification of 2015, on a single glass slide. In our cohort this classification algorithm showed significant differences in overall survival of the therapeutically important subgroups, which reflects the accuracy of the assay. To investigate the biology of NSCLC subtypes further, several proteins involved in carbohydrate metabolism were analyzed. In a hierarchical cluster analysis it could be shown that adenocarcinoma and squamous cell carcinoma harbor different metabolic shifts and, furthermore, that two distinct groups of squamous cell carcinoma seem to exist, a hypoxia and a transporter type. These results could be verified by analysis of mRNA data obtained from the TCGA database. As a close association between tumor metabolism and anti-tumor immune response has been reported, the lymphocytic infiltrates were characterized with respect to T-cells and their location within the tumor. Besides a negative correlation of lymphocyte density and expression of lactate dehydrogenase, it could be shown that depending on the location and type a high lymphocyte density indicates a significantly better overall survival of NSCLC patients. Investigating the expression of PD-L1 in NSCLC cells, a significant correlation with lymphocyte density was detected. In conclusion, the multi-antibody assay is a new and economically attractive tool for a reliable subclassification of NSCLC. This subtyping results in a better biological stratification of NSCLC and is the basis not only for palliative treatment options but also for further investigations on NSCLC biology. It was discovered that metabolic changes during malignant transformation are different in adenocarcinoma and squamous cell carcinoma. The latter group can be further divided into a hypoxia and a transporter type. Anti-tumor immune responses are influenced by the metabolic shift in NSCLC and lymphocyte density with respect to the location within the tumor is of prognostic significance in NSCLC. Therefore, the results contribute to a better biological understanding of NSCLC and may lead to new treatment options by targeting metabolic enzymes or triggering anti-tumor responses.

Keywords: Immunohistochemistry; Lymphocytes; Metabolism; Multi-antibody assay; Tumor immunology.