Proteogenomic insights into early-onset endometrioid endometrial carcinoma: predictors for fertility-sparing therapy response.

Endometrial carcinoma remains a public health concern with a growing incidence, particularly in younger women. Preserving fertility is a crucial consideration in the management of early-onset endometrioid endometrial carcinoma (EEEC), particularly in patients under 40 who maintain both reproductive desire and capacity. To illuminate the molecular characteristics of EEEC, we undertook a large-scale multi-omics study of 215 patients with endometrial carcinoma, including 81 with EEEC. We reveal an unexpected association between exposome-related mutational signature and EEEC, characterized by specific CTNNB1 and SIGLEC10 hotspot mutations and disruption of downstream pathways. Interestingly, SIGLEC10Q144K mutation in EEECs resulted in aberrant SIGLEC-10 protein expression and promoted progestin resistance by interacting with estrogen receptor alpha. We also identified potential protein biomarkers for progestin response in fertility-sparing treatment for EEEC. Collectively, our study establishes a proteogenomic resource of EEECs, uncovering the interactions between exposome and genomic susceptibilities that contribute to the development of primary prevention and early detection strategies for EEECs.

GSK3ß and UCHL3 govern RIPK4 homeostasis via deubiquitination to enhance tumor metastasis in ovarian cancer.

Receptor-interacting protein kinase 4 (RIPK4) is increasingly recognized as a pivotal player in ovarian cancer, promoting tumorigenesis and disease progression. Despite its significance, the posttranslational modifications dictating RIPK4 stability in ovarian cancer remain largely uncharted. In this study, we first established that RIPK4 levels are markedly higher in metastatic than in primary ovarian cancer tissues through single-cell sequencing. Subsequently, we identified UCHL3 as a key deubiquitinase that regulates RIPK4. We elucidate the mechanism that UCHL3 interacts with and deubiquitinates RIPK4 at the K469 site, removing the K48-linked ubiquitin chain and thus enhancing RIPK4 stabilization. Intriguingly, inhibition of UCHL3 activity using TCID leads to increased RIPK4 ubiquitination and degradation. Furthermore, we discovered that GSK3ß-mediated phosphorylation of RIPK4 at Ser420 enhances its interaction with UCHL3, facilitating further deubiquitination and stabilization. Functionally, RIPK4 was found to drive the proliferation and metastasis of ovarian cancer in a UCHL3-dependent manner both in vitro and in vivo. Importantly, positive correlations between RIPK4 and UCHL3 protein expression levels were observed, with both serving as indicators of poor prognosis in ovarian cancer patients. Overall, this study uncovers a novel pathway wherein GSK3ß-induced phosphorylation of RIPK4 strengthens its interaction with UCHL3, leading to increased deubiquitination and stabilization of RIPK4, thereby promoting ovarian cancer metastasis. These findings offer new insights into the molecular underpinnings of ovarian cancer and highlight potential therapeutic targets for enhancing antitumor efficacy.

Preoperative and intraoperative assessment of myometrial invasion in patients with FIGO stage I non-endometrioid endometrial carcinoma-a large-scale, multi-center, and retrospective study.

INTRODUCTION: Myometrial invasion is a prognostic factor for lymph node metastases and decreased survival in non-endometrioid endometrial carcinoma patients. Herein, we explored the mode of myometrial invasion diagnosis in FIGO stage I non-endometrioid carcinoma and evaluated the differences in diagnostic efficiency among intraoperative frozen section (IFS), intraoperative gross examination (IGE), magnetic resonance imaging (MRI), and computed tomography (CT) in clinical practice. Finally, we suggested which test should be routinely performed. METHOD: This was a historical cohort study nationwide with 30 centers in China between January 2000 and December 2019. Clinical data, including age, histology, method of myometrial invasion evaluation (MRI, CT, IGE, and IFS), and final diagnosis of postoperative paraffin sections, were collected from 490 non-endometrioid endometrial carcinoma (serous, clear cell, undifferentiated, mixed carcinoma, and carcinosarcoma) women in FIGO stage I. RESULTS: Among the 490 patients, 89.59% presented myometrial invasion. The methods reported for myometrial invasion assessment were IFS in 23.47%, IGE in 69.59%, MRI in 37.96%, and CT in 10.20% of cases. The highest concordance was detected between IFS and postoperative paraffin sections (Kappa = 0.631, accuracy = 93.04%), followed by IGE (Kappa = 0.303, accuracy = 82.40%), MRI (Kappa = 0.131, accuracy = 69.35%), and CT (Kappa = 0.118, accuracy = 50.00%). A stable diagnostic agreement between IFS and the final results was also found through the years (2000-2012: Kappa = 0.776; 2013-2014: Kappa = 0.625; 2015-2016: Kappa = 0.545; 2017-2019: Kappa = 0.652). CONCLUSION: In China, the assessment of myometrial invasion in non-endometrioid endometrial carcinoma is often performed via IGE, but the reliability is relatively low in contrast to IFS. In clinical practice, IFS is a reliable method that can help accurately assess myometrial invasion and intraoperative decision-making (lymph node dissection or not). Hence, it should be routinely performed in non-endometrioid endometrial carcinoma patients.

It is not the time to abandon intraoperative frozen section in endometrioid adenocarcinoma: A large-scale, multi-center, and retrospective study.

INTRODUCTION: Stage IB (deep myometrial invasion) high-grade endometrioid adenocarcinoma (EA), regardless of LVSI status, is classified into high-intermediate risk groups, requiring surgical lymph node staging. Intraoperative frozen section (IFS) is commonly used, but its adequacy and reliability vary between reports. Hence, we determined the utility of IFS in identification of high-risk factors, including deep myometrial invasion and high-grade. METHOD: We retrospectively analyzed 9,985 cases operated with hysterectomy and diagnosed with FIGO stage I/II EA in postoperative paraffin section (PS) results at 30 Chinese hospitals from 2000 to 2019. We determined diagnostic performance of IFS and investigated whether the addition of IFS to preoperative biopsy and imaging could improve identification of high-risk factors. RESULTS: IFS and postoperative PS presented the highest concordance in assessing deep myometrial invasion (Kappa: 0.834), followed by intraoperative gross examination (IGE Kappa: 0.643), MRI (Kappa: 0.395), and CT (Kappa: 0.207). IFS and postoperative PS presented the highest concordance for high-grade EA (Kappa: 0.585) compared to diagnostic curettage (D&C 0.226) and hysteroscope (Hys 0.180). Sensitivity and specificity for detecting deep myometrial invasion were 86.21 and 97.20% for IFS versus 51.72 and 88.81% for MRI, 68.97 and 94.41% for IGE. These figures for detecting high-grade EA were 58.21 and 96.50% for IFS versus 16.42 and 98.83% for D&C, 13.43 and 98.64% for Hys. Parallel strategies, including MRI-IFS (Kappa: 0.626), D&C-IFS (Kappa: 0.595), and Hys-IFS (Kappa: 0.578) improved the diagnostic efficiencies of individual preoperative examinations. Based on the high sensitivity of IFS, parallel strategies improved the sensitivities of preoperative examinations to 89.66% (MRI), 64.18% (D&C), 62.69% (Hys), respectively, and these differences were statistically significant (p = 0.000). CONCLUSION: IFS presented reasonable agreement rates predicting postoperative PS results, including deep myometrial invasion and high-grade. IFS helps identify high-intermediate risk patients in preoperative biopsy and MRI and guides intraoperative lymphadenectomy decisions in EA.

Spatial heterogeneity of infiltrating T cells in high-grade serous ovarian cancer revealed by multi-omics analysis.

Tumor-infiltrating lymphocytes (TILs), especially CD8+ TILs, represent a favorable prognostic factor in high-grade serous ovarian cancer (HGSOC) and other tumor lineages. Here, we analyze the spatial heterogeneity of different TIL subtypes in HGSOC. We integrated RNA sequencing, whole-genome sequencing, bulk T cell receptor (TCR) sequencing, as well as single-cell RNA/TCR sequencing to investigate the characteristics and differential composition of TILs across different HGSOC sites. Two immune "cold" patterns in ovarian cancer are identified: (1) ovarian lesions with low infiltration of mainly dysfunctional T cells and immunosuppressive Treg cells and (2) omental lesions infiltrated with non-tumor-specific bystander cells. Exhausted CD8 T cells that are preferentially enriched in ovarian tumors exhibit evidence for expansion and cytotoxic activity. Inherent tumor immune microenvironment characteristics appear to be the main contributor to the spatial differences in TIL status. The landscape of spatial heterogeneity of TILs may inform potential strategies for therapeutic manipulation in HGSOC.

Risk Factors and Prognosis of Early Recurrence in Stage I-II Endometrial Cancer: A Large-Scale, Multi-Center, and Retrospective Study.

Objective: The aim of the present study was to determine overall survival (OS) and risk factors associated with early recurrence in patients with FIGO I-II stage endometrial carcinoma (EC). Methods: Clinical features were retrospectively extracted from the database of China Endometrial Cancer Consortium from January 2000 to December 2019. A total of 2,974 patients with Federation International of Gynecology and Obstetrics (FIGO) I-II stage endometrial cancer were included. Kaplan-Meier survival analysis was used to assess OS and disease-specific survival. Cox proportional hazard model and Fine-Gray model were used to determine the factors related to OS. Binary logistic regression model was used to determine independent predictors of early relapse patients. Results: Of these 2,974 ECs, 189 patients were confirmed to have relapse. The 5-year OS was significantly different between the recurrence and non-recurrence patients (p < 0.001). Three quarters of the relapse patients were reported in 36 months. The 5-year OS for early recurrence patients was shorter than late recurrence [relapse beyond 36 months, p < 0.001]. The grade 3 [odds ratio (OR) = 1.55, 95%CI 1.17-2.05, p = 0.002], lymphatic vascular infiltration (LVSI; OR = 3.36; 95%CI 1.50-7.54, p = 0.003), and myometrial infiltration (OR = 2.07, 95%CI 1.17-3.65, p = 0.012) were independent risk factors of early relapse. The protective factor of that is progesterone receptor (PR)-positive (OR = 0.50, 95%CI 0.27-0.92, p = 0.02). Bilateral ovariectomy could reduce recurrence risk rate (OR = 0.26, 95%CI 0.14-0.51, p < 0.001). Conclusion: The OS of early relapse EC is worse. Grade 3, LVSI, and myometrial infiltration are independent risk factors for early relapse EC. In addition, the protective factor is PR-positive for those people and bilateral salpingo-oophorectomy could reduce the risk of recurrence.

Inhibiting the IRE1α Axis of the Unfolded Protein Response Enhances the Antitumor Effect of AZD1775 in TP53 Mutant Ovarian Cancer.

Targeting the G2/M checkpoint mediator WEE1 has been explored as a novel treatment strategy in ovarian cancer, but mechanisms underlying its efficacy and resistance remains to be understood. Here, it is demonstrated that the WEE1 inhibitor AZD1775 induces endoplasmic reticulum stress and activates the protein kinase RNA-like ER kinase (PERK) and inositol-required enzyme 1α (IRE1α) branches of the unfolded protein response (UPR) in TP53 mutant (mtTP53) ovarian cancer models. This is facilitated through NF-κB mediated senescence-associated secretory phenotype. Upon AZD1775 treatment, activated PERK promotes apoptotic signaling via C/EBP-homologous protein (CHOP), while IRE1α-induced splicing of XBP1 (XBP1s) maintains cell survival by repressing apoptosis. This leads to an encouraging synergistic antitumor effect of combining AZD1775 and an IRE1α inhibitor MKC8866 in multiple cell lines and preclinical models of ovarian cancers. Taken together, the data reveal an important dual role of the UPR signaling network in mtTP53 ovarian cancer models in response to AZD1775 and suggest that inhibition of the IRE1α-XBP1s pathway may enhance the efficacy of AZD1775 in the clinics.

AZD5153 reverses palbociclib resistance in ovarian cancer by inhibiting cell cycle-related proteins and the MAPK/PI3K-AKT pathway.

The CDK4/6 inhibitor, palbociclib has recently entered clinic-trial stage for breast cancer treatment. However, translating its efficacy to other solid tumors has been challenging, especially for aggressive solid tumors. We found that the effect of palbociclib as a single agent was limited due to primary and acquired resistance in multiple ovarian cancer (OC) models. Among these, patient-derived organoid and xenograft models are two most representative models of drug responsiveness in patients with OC. In preclinical models, this study demonstrated that activated MAPK/PI3K-AKT pathway and cell cycle-related proteins induced the resistance to palbociclib, which was overcome by the addition of the bromodomain protein 4 (BRD4) inhibitor AZD5153. Moreover, this study revealed that AZD5153 and palbociclib had a synergistic lethal effect on inducing the cell cycle arrest and increasing apoptosis, even in RB-deficient cell lines. Based on these results, it is anticipated that this class of drugs, including AZD5153, which inhibit the cell cycle-related protein and MAPK/PI3K-AKT pathway, will exhibit synergistic effects with palbociclib in OC.

Implications of Isolated Para-Aortic Lymph Node Metastasis in Endometrial Cancer: A Large-Scale, Multicenter, and Retrospective Study.

Objective: To systematically evaluate lymph node metastasis (LNM) patterns in patients with endometrial cancer (EC) who underwent complete surgical staging, which included systematic pelvic and para-aortic lymphadenectomy. Methods: Four thousand and one patients who underwent complete surgical staging including systematic pelvic and para-aortic lymphadenectomy for EC were enrolled from 30 centers in China from 2001 to 2019. We systematically displayed the clinical and prognostic characteristics of patients with various LNM patterns, especially the PLN-PAN+ [para-aortic lymph node (PAN) metastasis without pelvic lymph node (PLN) metastasis]. The efficacy of PAN+ (para-aortic lymph node metastasis) prediction with clinical and pathological features was evaluated. Results: Overall, 431 of the 4,001 patients (10.8%) showed definite LNM according to pathological diagnosis. The PAN+ showed the highest frequency (6.6%) among all metastatic sites. One hundred fourteen cases (26.5%) were PLN-PAN+ (PAN metastasis without PLN metastasis), 167 cases (38.7%) showed PLN+PAN-(PLN metastasis without PAN metastasis), and 150 cases (34.8%) showed metastasis to both regions (PLN+PAN+). There was also 1.9% (51/2,660) of low-risk patients who had PLN-PAN+. There are no statistical differences in relapse-free survival (RFS) and disease-specific survival (DSS) among PLN+PAN-, PLN-PAN+, and PLN+PAN+. The sensitivity of gross PLNs, gross PANs, and lymphovascular space involvement (LVSI) to predict PAN+ was 53.8 [95% confidence interval (CI): 47.6-59.9], 74.2 95% CI: 65.6-81.4), and 45.8% (95% CI: 38.7-53.2), respectively. Conclusion: Over one-fourth of EC patients with LMN metastases were PLN-PAN+. PLN-PAN+ shares approximate survival outcomes (RFS and DSS) with other LNM patterns. No effective clinical methods were achieved for predicting PAN+. Thus, PLN-PAN+ is a non-negligible LNM pattern that cannot be underestimated in EC, even in low-risk patients.

Lipopolysaccharide Affects the Proliferation and Glucose Metabolism of Cervical Cancer Cells Through the FRA1/MDM2/p53 Pathway.

Previous studies have found that LPS and FRA1 play opposite roles in cervical cancer. In addition, LPS functions by regulating the expression of FRA1 in many disease models, but there is currently no study of their relationship in the energy metabolism of tumor cells. This study, therefore, investigates the effects of LPS on FRA1-mediated glucose metabolism and the possible mechanisms it may have in cervical cancer cells. We constructed FRA1 stable overexpressing/ empty vector cervical cancer cell lines, where glucose consumption, the level of lactic acid production and the expression of energy metabolism related molecules were detected under the stimulation of LPS. At the same time, the changes in proliferation ability of cervical cancer cells were detected. We discovered that LPS promotes glucose consumption, lactic acid production, pentose phosphate bypass, and inhibits aerobic oxidation, by inhibiting the expression of FRA1; and that LPS promotes the growth of cervical cancer cells. Our results indicate that LPS affects the proliferation and glucose metabolism of cervical cancer cells through the FRA1/MDM2/p53 pathway.

The Immunological Role of CDK4/6 and Potential Mechanism Exploration in Ovarian Cancer.

Background: Ovarian cancer (OC) is one of the most lethal gynecologic cancers. Growing evidence has proven that CDK4/6 plays a key role in tumor immunity and the prognosis of many cancers. However, the expression and function of CDK4/6 in OC remain unclear. Therefore, we aimed to explore the influence of CDK4/6 in OC, especially on immunity. Methods: We analyzed CDK4/6 expression and prognosis using The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) and Genotype Tissue Expression (GTEx) data. Subsequently, we used the cytoHubba plug-in of Cytoscape software and starBase to identify the noncoding RNAs (ncRNAs) regulating CDK4/6. Finally, we verified the effect of CDK4/6 on immunity in OC cell lines and animal models. Results: CDK4/6 expression was higher in OC tissues than in normal ovarian tissues, and the high expression levels of CDK4/6 contributed to the immunosuppressive state of OC and were thus related to the poor prognosis of OC patients. This was also in general agreement with the results of OC cell line and animal experiments. Mechanistically, the CDK4/6 inhibitor palbociclib increased the secretion of interferon (IFN)-γ and the interferon-stimulated gene (ISG) response, thereby upregulating the expression of antigen-presenting molecules; this effect was partly dependent on the STING pathway and thus activated immunity in OC. Additionally, according to public data, the LRRC75A-AS1-hsa-miR-330-5p axis could inhibit the immune response of OC patients by upregulating CDK4/6, leading to a poor prognosis. Conclusion: CDK4/6 affects the immune microenvironment of OC and correlates with the prognosis of OC patients.

Hysteroscopic treatment of cesarean scar defect.

OBJECTIVE: To investigate the effect of hysteroscopic surgery on the outcomes of obstetrics and gynecology among patients with cesarean section diverticulum. METHODS: Ninety-nine infertile patients with cesarean section diverticulum received hysteroscopic treatment and were retrospectively analyzed. Patients were followed for 1 year. RESULTS: The study included ninety-nine symptomatic patients with cesarean section diverticulum. After surgery, the menstrual periods of patients were improved from 11.15 ± 4.44 to 7.69 ± 2.85 days. Forty-seven (47/99) women became pregnant after surgery. The number of patients who became pregnant with an anteflexion uterus after hysteroscopic surgery is 32 (32/57), and the number of women who became pregnant with a retroflexion uterus is 15 (15/42). CONCLUSION: Hysteroscopic surgery could improve the PCSD-associated prolonged menstrual bleeding, and satisfactory obstetrical outcomes could be achieved by the surgery treatment in women with cesarean defect.

All-trans retinoic acid enhances the effect of Fra-1 to inhibit cell proliferation and metabolism in cervical cancer.

OBJECTIVES: This study on all-trans retinoic acid was designed to explore its effect on the ability of Fra-1 to cervical cancer cell development. The results show that all-trans retinoic acid enhances the effect of Fra-1 on inhibiting cervical cancer proliferation and the glucose consumption, its effect on the loss of mitochondrial membrane potential, on the decreasing of lactic acid as well as ATP, and also influences the expression of MDM2/P53/P21 and LDHA. RESULTS: The results show that the expression of Fra-1 is higher in all-trans retinoic acid-treated cervical cancer. Flow cytometry and kit detection show that all-trans retinoic acid can enhance the ability of Fra-1 to lose the mitochondrial membrane potential, inhibit the glucose consumption and the production of lactic acid as well as ATP. CCK8 and colony formation assays indicate that all-trans retinoic acid enhances the ability of Fra-1 to inhibit cell proliferation. In addition, through Western blot analysis, it was determined that P53 and P21 were up-regulated, and MDM2 and LDHA were down-regulated. CONCLUSION: The overall results of the study strongly suggest that all-trans retinoic acid enhances the effect of Fra-1 on inhibiting cervical cancer proliferation and metabolism in vitro, and also influences the expression of MDM2/P53/P21 and LDHA.

Expression and function of FRA1 protein in tumors.

AP-1 is a dimeric complex that is composed of JUN, FOS, ATF and MAF protein families. FOS-related antigen 1 (FRA1) which encoded by FOSL1 gene, belongs to the FOS protein family, and mainly forms an AP-1 complex with the protein of the JUN family to exert an effect. Regulation of FRA1 occurs at levels of transcription and post-translational modification, and phosphorylation is the major post-translational modification. FRA1 is mainly regulated by the mitogen-activated protein kinases signaling pathway and is degraded by ubiquitin-independent proteasomes. FRA1 can affect biological functions, such as tumor proliferation, differentiation, invasion and apoptosis. Studies have demonstrated that FRA1 is abnormally expressed in many tumors and plays a relevant role, but the specific condition varies from the target organs. FRA1 is overexpressed in breast cancer, lung cancer, colorectal cancer, prostate cancer, nasopharyngeal cancer, thyroid cancer and other tumors. However, the expression of FRA1 is decreased in cervical cancer, and the expression of FRA1 in ovarian cancer and oral squamous cell carcinoma is still controversial. In this review, we present a detailed description of the regulatory factors and functions of FRA1, also, the expression of FRA1 in various tumors and its function in relative tumor.

The Jun N-terminal kinases signaling pathway plays a "seesaw" role in ovarian carcinoma: a molecular aspect.

Ovarian cancer is the most common gynecological malignancy that causes cancer-related deaths in women today; this being the case, developing an understanding of ovarian cancer has become one of the major driving forces behind cancer research overall. Moreover, such research over the last 20 years has shown that the Jun N-terminal kinase (JNK) signaling pathway plays an important role in regulating cell death, survival, growth and proliferation in the mitogen-activated protein kinases (MAPK) signaling pathway, an important pathway in the formation of cancer. Furthermore, the JNK signaling pathway is often regulated by an abnormal activation in human tumors and is frequently reported in the literature for its effect on the progression of ovarian cancer. Although the FDA has approved some JNK inhibitors for melanoma, the agency has not approved JNK inhibitors for ovarian cancer. However, there are some experimental data on inhibitors and activators of the JNK signaling pathway in ovarian cancer, but related clinical trials need to be further improved. Although the Jun N-terminal kinase (JNK) signaling pathway is implicated in the formation of cancer in general, research has also indicated that it has a role in suppressing cancer as well. Here, we summarize this seemingly contradictory role of the JNK signaling pathway in ovarian cancer, that 'seesaws' between promoting and suppressing cancer, as well as summarizing the application of several JNK pathway inhibitors in cancer in general, and ovarian cancer in particular.

lncRNA ABHD11-AS1, regulated by the EGFR pathway, contributes to the ovarian cancer tumorigenesis by epigenetically suppressing TIMP2.

OBJECTIVE: Epithelial ovarian cancer (EOC) is a common gynecologic malignancy characterized by extensive peritoneal metastasis and high mortality rate. ABHD11 Antisense RNA1 (ABHD11-AS1) has recently been identified as a regulator of growth and metastasis in multiple tumors, including EOC. However, the biological function and potential mechanism of ABHD11-AS1 in EOC remains poorly understood. METHODS: Immunohistochemistry, western blot, and qRT-PCR analysis were used to determine the expression pattern of ABHD11-AS1 and epidermal growth factor receptor (EGFR) in both EOC tissues and cell lines, respectively. Colony formation, transwell and wound healing assays were performed to evaluate the roles of EGFR and ABHD11-AS1 on the capacity of cell proliferation, migration, and invasion. Western blot analysis was performed to measure the regulation of EGFR pathway on STAT3. Moreover, chromatin immunoprecipitation was employed to demonstrate the interaction between ABHD11-AS1 and STAT3. RNA immunoprecipitation was subjected to prove the direct binding between ABHD11-AS1 and EZH2. Immunofluorescence staining was performed to measure the expression and localization of TIMP2. EOC mouse model was conducted for validating the role of ABHD11-AS1 in vivo. RESULTS: EGFR and ABHD11-AS1 were highly expressed in EOC tissues and cell lines. Knockdown of EGFR or ABHD11-AS1 inhibited cell growth, migration, and invasion of EOC cells. Expression of ABHD11-AS1 was regulated by the activation of EGFR signaling pathway, mediated by STAT3. Besides, ABHD11-AS1 was shown to silence TIMP2 by binding to chromatin-modifying enzyme EZH2. Furthermore, inhibition of EGFR pathway or ABHD11-AS1 repressed the tumor growth of EOC. CONCLUSION: We defined the regulatory relationship between the EGFR signaling pathway, ABHD11-AS1, EZH2, and TIMP2 suggesting that ABHD11-AS1 may act as an oncogene and a potential target for antitumor therapies in ovarian cancer.

M2-like tumor-associated macrophages-secreted EGF promotes epithelial ovarian cancer metastasis via activating EGFR-ERK signaling and suppressing lncRNA LIMT expression.

Background: Ovarian cancer (OC) is the gynecologic malignant tumor with high mortality. Accumulating evidence indicates that M2-like tumor-associated macrophages (TAMs) can secret EGF to participate in ovarian cancer growth, migration, and metastasis. An EGF-downregulated lncRNA, LIMT (lncRNA inhibiting metastasis), was identified as a critical regulator of mammary cell migration and invasion. Nevertheless, whether EGF secreted from M2-like TAMs regulates LIMT expression in ovarian cancer progression remains largely unknown. Methods: The human OC cell lines OV90 and OVCA429 were recruited in this study. The differentiation of the human monocyte cell line THP-1 into M2-like TAMs was confirmed using flow cytometry within the application of phorbol 12-myristate 13-acetate (PMA). ELISA was performed to detect EGF concentration in co-culture system of M2-like TAMs and OC cell lines. Moreover, CCK-8, flow cytometry and immunofluorescence staining of Ki67 were performed to assess the capacity of cell proliferation. Besides, cell migration and invasion were determined by wound healing and transwell assays. Furthermore, the expression levels of epithelial-mesenchymal transition (EMT) markers and EGFR/ERK signals were analyzed by qRT-PCR and western blot. Female athymic nude mice (8-12 weeks of age; n = 8 for each group) were recruited for in vivo study. Results: In the present study, THP-1 cells exhibited the phenotype markers of M2-like TAMs with low proportion of CD14+ marker and high proportion of CD68+, CD204+, CD206+ markers within the application of PMA. After co-culturing with M2-like TAMs, EGF concentration in the supernatants was significantly increased in a time-dependent manner. Besides, OC cells presented better cell viability, higher cell proliferation, and stronger migration and invasion. The expression of EMT-related markers N-cadherin, Vimentin and EGFR/ERK signals were markedly up-regulated, while E-cadherin was significantly decreased. However, these effects induced by co-culture system were reversed by the application of AG1478 (an EGFR inhibitor) or LIMT overexpression. Furthermore, the endogenous expression of LIMT was decreased in OC cell lines compared with the control group. Also, the in vivo experiments verified that the inhibition of EGFR signaling by AG1478 or overexpression of LIMT effectively repressed the tumor growth. Conclusion: Taken together, we demonstrated that EGF secreted by M2-like TAMs might suppress LIMT expression via activating EGFR-ERK signaling pathway to promote the progression of OC.