Seperation And Identification Of Secreted Serum Markers Of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors with high incidence and mortality in China. There is no specific serum marker yet. To separate and identify ESCC associated serum proteins/peptides would much improve the early diagnosis as well as elucidating the mechanism of the tumorigenesis of ESCC.In the present study, we used 2-DE/mass spectrometry-based proteomic approach to profile the proteins in ESCC serum. Five pairs of pre-/post surgery and twelve pairs of cancer/normal sera of ESCC had been separated by 2-DE assay. Twenty differentiated spots had been found on the 2-DE maps and three of them had been identified as clusterin which was decreased sharply in ESCC serum via MALDI-TOF-MS. This data was confirmed additionally by Western blot and RT-PCR.Clusterin was lost in EC0132 and EC0156 of ESCC cells and adult normal squmous epithelia of esophagus unless some keratinized one. Clusterin was localized in the connective tissue of the lamina propria of epithelial mucosa, in which the cytoplasm of esophageal glandular cells, plasma membrane and cytoplasm of duct glandular epithelia, and plasma membrane and cytoplasm of lymphocytes in lymphatic follicle were detected clusterin positive by immunohistochemistry staining. Clusterin was not expressed in ESCC tissues except some well-differentiated tumor cells were, sometimes, found positive.RT-PCR indicated clusterin was expressed in many fetal tissues.