COEXPRESSION OF RAS P21 AND EPIDERMAL GROWTH-FACTOR RECEPTOR DURING VARIOUS STAGES OF TUMOR PROGRESSION IN ORAL MUCOSE

Ras p21 and epidermal growth factor receptor (EGFR) have commonly been implicated in a variety of malignancies. The present study immunohist ochemically analysed the relationship between the expression of ras p2 1 and EGFR in normal, premalignant and malignant lesions of the oral m ucosa. Except for normal mucosa, all other lesions showed a more or le ss similar expression pattern of both ras p21 and EGFR. It was also ob served that the expression of both proteins was mostly confined to the basal or basaloid cells of the leucoplakia and carcinoma lesions, res pectively. Normal keratinizing type mucosa showed expression of ras p2 1 and EGFR in the basal and lower spinal cells. However, in non-kerati nizing mucosa the expression of ras p21 was totally negative while EGF R was restricted to the basal cells. Statistical analysis revealed a g ood correlation between the expression of ras p21 and EGFR with the va rious histological stages of tumour progression. The presence of these proteins in immature dividing cells of premalignant and malignant les ions thus emphasizes their relationship with cell proliferation.