Reference spectra from squamous epithelium and connective tissue allow whole section proteomics analysis

Abstract

We reasoned that micro-dissection of tumour cells for protein expression studies should be omitted since tumour-stroma interactions are an important part of the biology of solid tumours. To study such interactions in head and neck squamous cell carcinoma (HNSCC) development, we generated reference protein spectra for normal squamous epithelium and connective tissue by SELDI-TOF-MS. Calgranulins A and B, Annexin1 and Histone H4 were found to be strongly enriched in the epithelium. The alpha-defensins 1-3 and the haemoglobin subunits were identified in the connective tissue. Tumour-distant epithelia, representing early pre-malignant lesions, showed up-regulated expression of the stromal alpha-defensins, whereas the epithelial Annexin 1 was down-regulated. Thus, tumour microenvironment interactions occur very early in the carcinogenic process. These data demonstrate that omitting micro-dissection is actually beneficial for studying changes in protein expression during development and progression of solid tumours.

Key words::

• Proteomics
• HNSCC
• tumour microenvironment
• field cancerization
• protein biomarkers.

Acknowledgements

We specially thank the CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for financial support to M. Roesch-Ely. We thank Dr. Christa Flechtenmacher, Pathologisches Institut der Universität Heidelberg, for histopathological assessment, and Antje Schuhmann, Ines Kaden and Nataly Henfling for excellent technical assistance.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.