THYMOMA - TUMOR TYPE RELATED TO EXPRESSION OF EPIDERMAL GROWTH-FACTOR(EGF), EGF-RECEPTOR, P53, V-ERB, AND RAS P21

As clinicopathological features may not be sufficient to predict the p rogression of thymoma, We have carried out what we believe to be the f irst immunohistochemical study describing the relationship between the different types of thymoma and the tumour stage, on the one hand, and the expression of epidermal growth factor (EGF), EGF-receptor (EGFR), p53, v-erb B and ras p21, on the other. The positive rates versus his tological types and Masaoka's clinical stages in the 47 cases were as follows: p53 (non-invasive thymoma: 41.7%; malignant thymoma category I: 82.4%; malignant thy moma category II: 83.3%), EGF (non-invasive th ymoma: 4.2%; malignant thymoma category I: 11.8%; malignant thymoma ca tegory II: 33.3%) and EGFR (noninvasive thymoma: 8.3%; malignant thymo ma category I: 35.3%; malignant thymoma category II: 66.7%); p53 (stag es I and II: 51.7%; stages III and IV: 77.8%), EGF (stages I and II: 3 .4%; stages III and IV: 22.2%) and EGFR (stages I and II: 13.8%; stage s III and IV: 44.4%). These data suggest that p53 may be implicated in the initial stages of tumorigenesis and that increased expression of EGF and EGFR may play a role in thymoma progression.