Squamous cell carcinomas, an immunohistochemical and ultrastructural study.

Fourty-seven squamous cell carcinomas (SCCs) were studied by light microscopy, immunohistochemistry and electronmicroscopy. Nineteen percent (9 cases) of SCCs in different locations were immunoreactive for CAM5.2 and three poorly differentiated SCCs did not express cytokeratins 6 and 18. No cases were positive for c-erbB2 protein. p53 protein overexpression was found in malignant cells in 40% of the primary tumours and in 60% of the lymph node metastases. Four poorly differentiated SCCs expressed vimentin and in these cases the tumour cells had accumulations of less dense intermediate filaments in cytoplasm.