Endometrial cancers are complex ecosystems composed of cells with distinct phenotypes, genotypes, and epigenetic states. Current models do not adequately reflect oncogenic origin and pathological progression in patients. Here we use single-cell RNA sequencing to profile cells from normal endometrium, atypical endometrial hyperplasia, and endometrioid endometrial cancer (EEC), which altogether represent the step-by-step development of endometrial cancer. We find that EEC originates from endometrial epithelial cells but not stromal cells, and unciliated glandular epithelium is the source of EEC. We also identify LCN2 + /SAA1/2 + cells as a featured subpopulation of endometrial tumorigenesis. Finally, the stromal niche and immune environment changes during EEC progression are described. This study elucidates the evolution of cell populations in EEC development at single-cell resolution, which would provide a direction to facilitate EEC research and diagnosis.

Objective: To assess the efficacy of metformin in megestrol acetate (MA)‐based fertility‐sparing treatment for patients with atypical endometrial hyperplasia (AEH) and endometrioid endometrial cancer (EEC).Design: A randomised, single‐centre, open‐label, controlled trial conducted between October 2013 and December 2017.Setting: Shanghai OBGYN Hospital of Fudan University, China.Population: A total of 150 patients (18–45 years old) with primary AEH or well‐differentiated EEC were randomised into an MA group (n = 74) and an MA plus metformin group (n = 76).Methods: Patients with AEH or EEC were firstly stratified, then randomised to receive MA (160 mg orally, daily) or MA (160 mg orally, daily) plus metformin (500 mg orally, three times a day).Main outcomes and measures: The primary efficacy parameter was the cumulate complete response (CR) rate within 16 weeks of treatment (16w‐CR rate); the secondary efficacy parameters were 30w‐CR rate and adverse events.Results: The 16w‐CR rate was higher in the metformin plus MA group than in the MA‐only group (34.3 versus 20.7%, odds ratio [OR] 2.0, 95% confidence interval [CI] 0.89–4.51, P = 0.09) but the difference was more significant in 102 AEH patients (39.6 versus 20.4%, OR 2.56, 95% CI 1.06–6.21, P = 0.04). This effect of metformin was also significant in non‐obese (51.4 versus 24.3%, OR 3.28, 95% CI 1.22–8.84, P = 0.02) and insulin‐sensitive (54.8 versus 28.6%, OR 3.04, 95% CI 1.03–8.97, P = 0.04) subgroups of AEH women. No significant result was found in secondary endpoints.Conclusion: As a fertility‐sparing treatment, metformin plus MA was associated with a higher early CR rate compared with MA alone in AEH patients.Tweetable For AEH patients, metformin plus MA might be a better fertility‐sparing treatment to achieve a higher early CR rate compared with MA alone.

This study aimed to evaluate the efficacy of comprehensive hysteroscopic evaluation and lesion resection combined with progestin therapy in young patients with endometrial atypical hyperplasia (EAH) and early stage endometrial cancer (EEC) who wished to preserve their fertility. Patients with EAH (n = 120) or well-differentiated EEC (n = 40, FIGO stage IA, without myometrial invasion) were retrospectively included. All patients received constant oral progestin combined with hysteroscopic evaluation every 3 months until achieving complete response (CR). The location, number and size of each suspected lesion or cluster were detailly recorded during the hysteroscopy. The median age was 32.0 year-old (range, 22-47 year-old). Totally 148 patients (97.4%) achieved CR while 3 EAH and 1 EEC patients presented with disease progression, and 8 patients were still in treatment. The mean treatment duration for achieving CR was 6.7 ± 0.3 months (range, 1-18 months). After adjusting for patient age, body mass index (BMI), history of pregnancy and type of conservative therapies, lesion size ≤2 cm (OR, 0.701; 95% CI, 0.496-0.991; P = 0.045) was significantly correlated with shorter treatment time to achieve CR. Among 60 patients attempted to conceive after achieving CR, 45.0% (15/60) had been pregnant, 25.0% (15/60) delivered live birth, 13.3% (8/60) are still in pregnancy, while 6.7% experienced spontaneous abortion. Comprehensive hysteroscopic evaluation and lesion resection plus progestin therapy seem to be an effective and safe fertility sparing therapy for patients with EAH or EEC. Endometrial lesion size ≤2 cm correlated with a shorter treatment period to achieve CR.

Persistent unopposed estrogen stimulation is a central oncogenic mechanism driving the formation of type I endometrial cancer. Recent epidemiologic and clinical studies of endometrial cancer have also revealed a role for insulin resistance, clinically manifested by chronic inflammation. However, the role of inflammation in estrogen-driven endometrial cancer is not well characterized. In this study, we investigated the association between infiltrating macrophages and estrogen sensitivity in endometrial cancer. Evaluating tissue samples and serum from patients with precancerous lesions or endometrial cancer, we found that tissue macrophage infiltration, but not serum estradiol levels, correlated positively with endometrial cancer development. Furthermore, IL4/IL13-induced CD68⁺CD163⁺ macrophages enhanced the proliferative effects of estradiol in endometrial cancer cells by upregulating estrogen receptor alpha (ERα), but not ERβ. Mechanistic investigations revealed that CD68⁺CD163⁺ macrophages secreted cytokines, such as IL17A, that upregulated ERα expression through TET1-mediated epigenetic modulation of the ERα gene. Overall, our findings show how cytokines produced by infiltrating macrophages in the endometrial microenvironment can induce epigenetic upregulation of ERα expression, which in turn sensitizes endometrial cells to estrogen stimulation. The concept that inflammation-induced estrogen sensitivity in the endometrium acts as a driver of type I endometrial cancer has implications for infiltrating macrophages as a prognostic biomarker of progression in this disease setting. Cancer Res; 76(6); 1354–66. ©2016 AACR.

Yang B, et al. J Gynecol Oncol. 2017 Dec;29:e35. https://doi.org/10.3802/jgo.2018.29.e35

Guan J, et al. J Gynecol Oncol. 2018 Aug;30:e13. https://doi.org/10.3802/jgo.2019.30.e13