Expression of estrogen receptor, progesterone receptor, and insulin-like growth factor receptor-1 and of MIB-1 in patients with recurrent pleomorphic adenoma of the parotid gland.

Abstract

Patients with recurrent pleomorphic adenomas of the parotid gland are difficult to manage without considerable risk of facial nerve injury. The prognostic significance of progesterone receptor (PR) and estrogen receptor (ER) reported in these adenomas was evaluated in patients with recurrent pleomorphic adenomas, comparing the results in a group of patients with primary adenomas without recurrences during 10 years of follow-up. Paraffin embedded tumor samples from 52 patients with recurrent pleomorphic adenoma of the parotid gland were collected and stained immunohistochemically. Expression of PR, ER, Ki-67 antigen, and insulin-like growth factor receptor-1 (IGFR-1) was analyzed in resected samples of recurrent tumors and was compared with samples from a control group of patients with primary pleomorphic adenoma. A difference (P < 0.05) in the type of tumor was observed between the recurrent group (more cell-poor variants) and the control group. ER expression was low in both groups (19% and 17%, respectively), but immunoreactivity for ER was higher (48%) in normal parotid gland tissue. PR expression in the recurrent group (96%) was higher compared with PR expression in the control group (61%; P < 0.001). PR expression and IGFR-1 expression were correlated weakly (correlation coefficient = 0.660; P = 0.053) in the recurrent group. The expression of growth fraction (Ki-67 score) and IGFR-1 was similar in both groups but was more extensive compared with normal parotid gland tissue. PR seems to be a prognostic factor in recurrent pleomorphic adenoma of the parotid gland. The PR pathway can be considered a potential target for hormone treatment in patients with these recurrent adenomas.