Hormone Receptor Expression and Activity for Different Tumour Locations in Patients with Advanced and Recurrent Endometrial Carcinoma.

Simple Summary: Oestrogen and progesterone are two sex hormones that are important in the development of cancer of the inner lining of the uterus and endometrial cancer (EC). Oestrogen binds to the oestrogen receptor (ER) and progesterone to the progesterone receptor (PR). The presence of these receptors is important because the response to hormonal therapy is higher when the receptors are present. However, as EC grows and spreads throughout the body, ER and PR may be lost. In this study, we found that tumours that have spread to other organs throughout the blood and tumours that have spread in the abdomen have a relatively high presence of ER/PR, while tumours located in the lymph nodes have a lower presence of PR. ER/PR-IHC were not lower in tumours that had previously been treated with radiotherapy. This might influence the application of hormonal therapy in the future. Background: Response to hormonal therapy in advanced and recurrent endometrial cancer (EC) can be predicted by oestrogen and progesterone receptor immunohistochemical (ER/PR-IHC) expression, with response rates of 60% in PR-IHC > 50% cases. ER/PR-IHC can vary by tumour location and is frequently lost with tumour progression. Therefore, we explored the relationship between ER/PR-IHC expression and tumour location in EC. Methods: Pre-treatment tumour biopsies from 6 different sites of 80 cases treated with hormonal therapy were analysed for ER/PR-IHC expression and classified into categories 0–10%, 10–50%, and >50%. The ER pathway activity score (ERPAS) was determined based on mRNA levels of ER-related target genes, reflecting the actual activity of the ER receptor. Results: There was a trend towards lower PR-IHC (33% had PR > 50%) and ERPAS (27% had ERPAS > 15) in lymphogenic metastases compared to other locations (p = 0.074). Hematogenous and intra-abdominal metastases appeared to have high ER/PR-IHC and ERPAS (85% and 89% ER-IHC > 50%; 64% and 78% PR-IHC > 50%; 60% and 71% ERPAS > 15, not significant). Tumour grade and previous radiotherapy did not affect ER/PR-IHC or ERPAS. Conclusions: A trend towards lower PR-IHC and ERPAS was observed in lymphogenic sites. Verification in larger cohorts is needed to confirm these findings, which may have implications for the use of hormonal therapy in the future. [ABSTRACT FROM AUTHOR]