In Situ mRNA Hybridization and an Immunohistochemical Study of EGFR in Uterine Cervix Cancer

Ko, Hyang Mi; Park, Chang Soo; Juhng, Sang Woo

Abstract

Epidermal growth factor receptor (EGFR) is an intergral membrane protein. Overexpression or mutation of EGFR may play a role in careinogenesis. Recently, many molecular biologic techniques have been used to study expression of oncogenes. One of them, in situ mRNA hybridization, using paraffin embedded blocks, offers a unique means to allow precise localization within histological preparations, and also overcomes problems relating to translation defects and abnormal translation. In order to confirm the usefulness of epidermal growth factor receptor as a tumor marker, and to compare the expression of EGFR between in situ MRNA hybridization and an immunohistochemical study, in situ MRNA hybridization was performed along with an immunohistochemical study for EGFR in paraffin sections of 84 uterine cervix carcinomas. A positive reaction for EGFR was observed mairdy in the cytoplasm of tumor cells. The vascular muscle layer and uterine muscle tissue around the cancer nest revealed a positive reaction in immunohistochemical stain for EGFR, with a negative reaction for EGFR mRNA. In the cancer nests, the immunohistochemical positive reaction for EGFR was strong in differentiated cells and keratin pearls, but a strong positive reaction for EGFR mRNA was localized in undifferentiated cells. The overall positive of immunostaing for EGFR was 77% for uterine cervix carcinoma; 71 % for carcinoma in situ, 71 % for microinvaseve carcinoma, and 89% for invasive carcinoma. The overall positivity of EGFR from in situ MRNA hybridization was 94% of the uterine cervix carcinoma; 93% for carcinoma in situ, 93% for microinvasive carcinoma, and 96% for invasive carcinoma. From these results, EGFR is a useful tumor marker for uterine cervix carcinoma, and in situ mRNA hybridization has greater sensitivity and specificity than immunohistochemistry.