ESR1 and endometrial cancer: On the basis of above two parameters including SUVmax and tumour differentiation grade, we categorized endometrial cancers into three groups to infer their potential of being ER-positive: a low-potential group (SUVmax > 15.3 and poorly differentiated), a moderate-potential group (SUVmax < 15.3 and poorly differentiated, or SUVmax > 15.3 and well- or moderately differentiated), and a high-potential group (SUVmax < 15.3 and well- or moderately differentiated).