The Expression of Epidermal Growth Factor Receptor mRNA by in Situ Hybridization and the Prognosis in Transitional Cell Carcinoma of Bladder

Sim, Jaehong; Park, Yang Il; Park, Chang Soo

Abstract

Recently many molecular biologic techniques have been tried to determine a prognostic indicator in various malignancies by evaluating the capacity of cellular differentiation and proliferation and the degree of expression of oncogene products. It is suggested that the activation of EGFR may play a role in normal and abnormal cellular proliferation. Many reports have demonstrated that EGFR is overexpressed in genitourinary, breast, lung, head and neck tumors, and possibly used as tumor marker. In this study we measured EGFR mRNA by in situ hybridization in 64 patients with transitional cell carcinoma of bladder and 14 cases of normal bladder to evaluate its relation to the prognosis. The positive staining of EGFR mRNA by in situ hybridization was observed in 42.8% of normal urothelium and 100% of transitional cell carcinoma of bladder. The strong positive staining of EGFR mRNA was observed in 57.5% of superficial cancer of bladder and 80.6% of invasive one(Ta 25%, T1 62.1%, T2 72.7%, T3 76.9%, T4 100% and Grade I 35%, Grade II 75.9%, Grade III 94.4%, respectively). As tumor stage and grade was increased, the corresponding strong positivity of EGFR mRNA was significant. Progression to invasive cancer occurred in 3 patients with superficial cancer and 2 of them had strong positive EGFR mRNA finding in original specimen. Tumor recurrences occurred in 15 patients with superficial cancer and 8 of them had strong positive EGFR mRNA finding in original specimen. In 20 of the 25 patients(80%) who died of bladder cancer during the study tumors were EGFR mRNA strong positive. The death rate of patients with strong positive EGFR mRNA was significantly greater than that of patient with weak positive EGFR mRNA tumor. In conclusion, The EGFR mRNA expression of transitional cell carcinoma of bladder using in situ hybridization technique may be a useful tumor marker and prognostic indicator.