DIFFERENTIAL EXPRESSION OF EPIDERMAL GROWTH-FACTOR RECEPTOR IN HUMAN HEAD AND NECK CANCERS

Background. Over-expression of human epidermal growth factor receptor (EGFR) is associated with a variety of human malignancies, including h ead and neck cancer. It has also been studied for its effect on cancer cell responses to chemotherapy. To accurately measure changes in EGFR expression that might be of diagnostic or prognostic importance in he ad and neck cancers, a quantitative assay for the direct detection of EGFR messenger ribonucleic acid (mRNA) was developed. Methods. Our met hod was based on competitive reverse transcriptase-polymerase chain re action (RT-PCR) that was able to measure EGFR mRNA levels undetectable by northern-blot analysis. We measured EGFR mRNA by RT-PCR in human h ead and neck cancers and their corresponding adjacent, histologically normal tissues and in cisplatin-treated and untreated oral epithelial cell lines. Results. All the tumor samples had higher EGFR mRNA levels than their corresponding adjacent normal tissues. It is also shown th at EGFR mRNA levels in normal oral epithelial cells were elevated afte r exposure to cisplatin. In contrast, EGFR mRNA levels in oral cancer cells were decreased after the exposure, suggesting that increased EGF R expression may have different functions in cancer cells and in norma l cells under stress. Conclusions. Accurate monitoring of EGFR express ion may be a useful marker for diagnosis, treatment, and prognosis of head and neck cancer. (C) 1998 John Wiley & Sons, Inc.