S100A2-S100P expression profile and diagnosis of non-small cell lung carcinoma: impairment by advanced tumour stages and neoadjuvant chemotherapy.

Early and correct diagnosis of non-small cell lung carcinoma (NSCLC) is essential for the choice of an appropriate anti-cancer therapy. Besides the histopathological diagnosis, molecular profiling by detection of the tumour-associated gene expression might play an upcoming role. As proteins of the S100 gene family show a distinct cell type-specific expression profile, our study focused on the relevance of the S100 family for identification and classification of NSCLCs. Among the S100 members, we identified the expression of S100A1, S100A2, S100A4, S100A6, S100A9 and S100P in human lung carcinoma cells (H358(p53-), A549(p53+)) or NSCLC tissues. Distinct S100 members are increased in NSCLCs compared with control lung specimens depending on the histopathological subtype. In particular, S100A2 was upregulated in squamous cell carcinomas, whereas S100P was mainly increased in adenocarcinomas. The upregulation of either S100A2 or S100P was detected in early but less in advanced tumour stages and not at all in NSCLC patients who had received neoadjuvant chemotherapy. In conclusion, our study indicates an important role of the S100A2-S100P expression profile for molecular diagnosis of NSCLCs at early and, therefore, prognostically more favourable tumour stage. As the S100A2-S100P profile also allows the histopathological classification, it might significantly support the conventional tumour diagnostics.