Expression of estrogen receptor, progesterone receptor, and Her-2/ neu in primary and extra-corporeal endometrial cancer

Abstract

Objective: To compare immunohistochemical (IHC) expression of estrogen receptor (ER), progesterone receptor (PR), and Her-2/neu in the primary tumors of endometrial cancer (EMC) and their extra-corporeal lesions.

Methods: Paraffin-embedded tissues of the primary and extra-corporeal tumors of EMC were retrieved for IHC study. Expression of ER, PR, and Her-2/ neu in the primary tumors and extra-corporeal lesions were compared.

Results: From 72 EMC patients with 87 extra-corporeal lesions, positive PR expression was significantly lower in the extra-corporeal lesions than that in the primary sites: 42.5% vs. 63.9%, respectively (p=0.007). No statistically significant differences of ER and Her-2/ neu expressions in the extra-corporeal and the primary sites were found: 42.5% and 55.6% for ER (p=0.102) and 20.7% vs. 13.9% for Her-2/ neu (p=0.262), respectively. The expression of extra-corporeal lesions were concordant to the primary tumor in 65.5% of ER (k=0.319), 71.2% of PR (k=0.445), and 83.9% of Her-2/ neu (k=0.413). From 15 cases wherein IHC from two extra-corporeal sites were studied, 73% had concordant ER expression between the two extra-corporeal lesions (k=0.412) while 93.3% had concordant PR and concordant Her-2/ neu expression (k=0.842 for PR and 0.634 for Her-2/ neu).

Conclusion: PR expression was significantly higher in the primary tumors than the extra-corporeal sites. Higher ER and lower Her-2/ neu expressions in the primary tumors were also observed but the differences were not significant. The tumors heterogeneity suggests it may be important to study tumor tissues from both primary and extra-corporeal sites when planning treatment, especially by hormonal or targeted therapies.