ASSESSMENT OF TUMOR MARKERS IN BENIGN, DYSPLASTIC AND MALIGNANT ORAL MUCOSAL LESIONS

Immunohistochemical demonstration of tumor-associated markers may be valuable as an adjunct to conventional histology for determination of malignancy development in oral mucosal diseases. Accordingly, the present study determined the distribution of some important tumor markers such as heat shock proteins (HSP), fibroblast growth factors (FGF) and transferrin receptors (TF-R) in 22 samples of primary oral squamous cell carcinoma (SCC) and in 18 hyperplastic/dysplastic oral lesions. Fifteen samples of normal buccal mucosa were included for comparison. Serial sections taken from frozen tissues and paraffin-embedded samples were stained immunohistochemically using monoclonal antibodies against HSP, FGF and TF-R. Results showed that normal tissues had only a detectable level ofHSP and FGF while dysplastic tissues had a higher level of HSP and FGF expression. Oral sces demonstrated the highest level of HSP and FGF expression distributed widely across the tumor specimens. TF-R expression was detected only in cryostat sections with low immunoreactivity seen in normal tissues, and the highest level of immunoreactivity detected in malignant tissues. Expression of TF-R in paraffin-embedded sections was non-specific and was masked by fixation methods used to process these tissues. It is concluded that HSP and FGF are largely expressed by malignant cells indicating that over-expression of these markers in mucosal lesions might be a reflection of malignancy. Secondly, these markers are preserved well in paraffin-embedded sections and finally, expression of TF-R correlates with rapid cell proliferation but its assessment is highly specific and is only accurate in cryostat sections.