Significance of S100A4 as a prognostic marker of lung squamous cell carcinoma.

Background: The prognostic significance of S100A as potential biomarker for breast cancer was reported; however, this finding has recently been challenged. Here, the aim was to assess whether S100A4 could also be a prognostic biomarker of lung cancer. Materials and Methods: A specific high-titer anti-S100A4 monoclonal antibody was developed. The utility and specificity of this antibody was validated by immunostaining experiments. The antibody was tested against a newly developed high-density tissue microarray including 400 lung cancer tissues to examine the clinico-pathological and prognostic significance of S100A4 in lung cancer. Results: The staining of S100A4 was significantly associated with patients' poor prognosis in lung squamous cell carcinoma but not lung adenocarcinoma. Conclusion: S100A4 seems to be a prognostic biomarker of lung squamous cell carcinoma (5-year survival rate of 38.5% versus 7.4% , p<0.01), but not of adenocarcinoma. The current trend in cancer treatment is shifting from uniform protocols to personally customized methods. The prediction of prognosis or therapy response has become central to the efficiency of customized cancer therapies. Prognosis is an important factor used to decide the extent of surgery. Immunohistochemistry is an excellent technique to link basic research data to therapy and is critical for the identification of specific proteins overexpressed in malignant tissues. Nevertheless, the prognostic significance of biomarkers identified using immunohistochemical analysis needs to be carefully validated by judging the specificity and sensitivity of the immunostaining protocol. Only after rigorous testing, can one determine if these proteins can be considered as suitable candidates as prognostic/predictive markers.