Epidermal growth factor receptor immunostaining and epidermal growth factor receptor-tyrosine kinase activity in...

Epidermal growth factor receptor (EGFR) expression and EGFR-tyrosine kinase (EGFR-TK) activity were measured in proliferative (n = 12) and neoplastic (n = 31) human endometrium. Immunoreactivity of EGFR was related to clinicopathological features, estrogen receptor (ER) and progesterone receptor (PR) status, and patient outcome. All proliferative and 27 neoplastic specimens expressed the EGFR. Expression of the EGFR was higher in proliferative endometrium than in endometrial cancer (p < 0.0001). ER immunostaining was observed in 19 of the endometrial carcinomas, while PR expression was demonstrated in only 12 neoplastic specimens. EGFR expression was not related to the ER/PR immunostaining in endometrial carcinomas. Clinicopathological features (age, stage, histological type, grade or depth of invasion) and clinical outcome were unrelated to EGFR immunoreactivity. EGFR-TK activity was detected in 29 of 31 endometrial neoplasms with a 9 times higher mean activity in neoplastic than in proliferative endometrial specimens. There was no relationship between the EGFR-TK activity and EGFR immunostaining in human neoplastic endometrium (p = 0.77). A trend towards a poorer outcome of patients with the EGFR-TK activity above 40 pmol/min/mg was observed, but was not statistically significant. These results support the view that the EGFR expression is downregulated in endometrial carcinomas compared to proliferative endometrial specimens.