[Correlation between esophageal cancer cell differentiation and expression of cytokeratin and tonofilament]

The expression of phenotypes of cultured cancer cells might be associated with cancer cell differentiation. By using the electron microscope and monoclonal antibodies against cytokeratins, PKK1, PKK2 and PKK3, the expression of cytokeratins and tonofilaments of normal embryonic esophageal epithelial cells and esophageal cancer cells were studied. Both PKK1 and PKK2 cytokeratins were detected in embryonic esophageal and esophageal cancer cells, but PKK3 was not present. This indicated that these were squamous but not glandular epithelial cells. Also, a much greater degree of expression of PKK1 and PKK2, tonofilaments and desmosomes was observed in differentiated embryonic squamous esophageal epithelial cells and in DMSO or retinamide induced differentiated esophageal cancer cells than in undifferentiated esophageal cancer cells.