ESR1 and endometrioid adenocarcinoma: In our current study with a large sample size of Chinese women from a single hospital (largest womens’ hospital in China), a higher frequencies of ER (>85%) or PR (> 58%) positivity were noted in serous and endometrioid carcinoma, whilst mucinous and clear cell carcinoma showed lower frequencies of ER (13-19%) or PR (4-24%) positivity.