HER2+ endometrioid endometrial cancer possesses distinct molecular and immunologic features associated with a more active immune microenvironment and worse prognosis

OBJECTIVE

HER2 status is not routinely evaluated in endometrioid endometrial cancer (E-EMCA), though it is frequently overexpressed or amplified in high grade E-EMCA and uterine serous carcinoma. Defining characteristics and survival outcomes of HER2+ E-EMCA could reveal subsets of patients who may benefit from targeted therapies.

METHODS

2927 E-EMCA tumors from the Caris Life Sciences database were analyzed by next-generation sequencing and whole exome sequencing, whole transcriptome sequencing, and immunohistochemistry for molecular and genomic features in a CLIA/CAP-certified laboratory (Caris Life Sciences, Phoenix, AZ). HER2 status was determined by transcriptomic cutoff extrapolated from uterine serous carcinoma. The relationship between HER2 status and patient outcomes was determined by Kaplan-Meier analysis.

RESULTS

HER2 positivity was detected in 5.47% of E-EMCA. Differences in molecular alterations based on HER2 status were most apparent in microsatellite stable (MSS) tumors, which displayed increased TP53 mutations and loss of heterozygosity (LOH) and decreased PTEN and CTNNB1 mutations. HER2+ tumors had increased immune checkpoint gene expression and immune cell infiltration, particularly among MSS tumors. All HER2+ tumors displayed increased MAPK pathway activation scores (MPAS) and patients with HER2+ tumors experienced worse overall survival.

CONCLUSIONS

HER2 positivity in E-EMCA corresponds with a unique molecular landscape, particularly in MSS tumors. HER2+ tumors are also associated with increased MAPK pathway activation and exhibit features of a more active immune microenvironment. These findings suggest a potential benefit of HER2 and MAPK targeted therapies as well as immunotherapies in this patient population.

GAS6-AXL Inhibition by AVB-500 Overcomes Resistance to Paclitaxel in Endometrial Cancer by Decreasing Tumor Cell Glycolysis

Chemotherapy is often ineffective in advanced-stage and aggressive histologic subtypes of endometrial cancer. Overexpression of the receptor tyrosine kinase AXL has been found to be associated with therapeutic resistance, metastasis, and poor prognosis. However, the mechanism of how inhibition of AXL improves response to chemotherapy is still largely unknown. Thus, we aimed to determine whether treatment with AVB-500, a selective inhibitor of GAS6-AXL, improves endometrial cancer cell sensitivity to chemotherapy particularly through metabolic changes. We found that both GAS6 and AXL expression were higher by immunohistochemistry in patient tumors with a poor response to chemotherapy compared with tumors with a good response to chemotherapy. We showed that chemotherapy-resistant endometrial cancer cells (ARK1, uterine serous carcinoma and PUC198, grade 3 endometrioid adenocarcinoma) had improved sensitivity and synergy with paclitaxel and carboplatin when treated in combination with AVB-500. We also found that in vivo intraperitoneal models with ARK1 and PUC198 cells had decreased tumor burden when treated with AVB-500 + paclitaxel compared with paclitaxel alone. Treatment with AVB-500 + paclitaxel decreased AKT signaling, which resulted in a decrease in basal glycolysis. Finally, multiple glycolytic metabolites were lower in the tumors treated with AVB-500 + paclitaxel than in tumors treated with paclitaxel alone. Our study provides strong preclinical rationale for combining AVB-500 with paclitaxel in aggressive endometrial cancer models.

Abstract LB081: GAS6-AXL inhibition by AVB-500 overcomes resistance to paclitaxel in endometrial cancer by decreasing tumor cell glycolysis

Objective/Background: Chemotherapy is often ineffective in advanced stage and aggressive histologic subtypes of endometrial cancer. Overexpression of the receptor tyrosine kinase AXL has been found to be associated with therapeutic resistance, metastasis, and poor prognosis in endometrial cancer. Our objective was to identify whether inhibition of AXL through a novel, selective targeted agent, AVB-500, would improve sensitivity to paclitaxel. Additionally, we sought to determine whether the mechanism for this improved sensitivity was through metabolic regulation.

Methods: Immunohistochemistry (IHC) was performed on a tissue microarray containing specimens from patients with primary and metastatic uterine serous carcinoma. Blind scoring was performed by two reviewers. Kaplan-Meier methods were used to generate time-to-event curves. Cell viability was performed with high-grade endometrial, chemo-resistant cell lines, ARK1 and PUC198. Cells were treated with paclitaxel and with AVB-500+paclitaxel. Intraperitoneal (IP) ARK1 or PUC198 tumors were treated with vehicle, AVB-500, paclitaxel, or AVB-500+paclitaxel. A Seahorse Analyzer was used for glycolytic rate assays. Isotope tracing was used for in vivo metabolite abundance quantification.

Results: We found that both GAS6 and AXL expression were higher by IHC in tumors with a poor response to chemotherapy compared to tumors with a good response to chemotherapy (GAS6: 40.9% vs. 30.4%, P=0.012; AXL: 60.7% vs. 42.7%, P=0.013). Median PFS and OS were longer in patients with low GAS6 expressing tumors compared to high GAS6 expressing tumors (PFS: 33.6 mo vs. 10.6 mo, P=0.003; OS: 39.5 mo vs. 27.7 mo, P=0.003). We showed that chemotherapy resistant endometrial cancer cell lines, ARK1 and PUC198 had improved sensitivity and synergy with paclitaxel when treated in combination with AVB-500. ARK1 and PUC198 in vivo IP models had significantly fewer tumors (ARK1: P=0.007; PUC198: P=0.029) and decreased tumor weight (ARK1: P<0.001; PUC198: P=0.006) when treated with AVB-500+paclitaxel vs. paclitaxel alone. Treatment with AVB-500 + paclitaxel decreased AKT signaling which resulted in a decrease in basal glycolysis. Finally, treatment with AVB-500 + paclitaxel decreased multiple glycolytic metabolites, including fructose-1,6-bisphosphate (P=0.002), 3-phosphoglyceric acid (P=0.014), phosphoenolpyruvate (P=0.013), and lactate (P=0.024) vs. treatment with paclitaxel alone.

Conclusions: Our study provides strong pre-clinical rationale for combining AVB-500 with paclitaxel in aggressive endometrial cancer models. Additionally, continued identification of viable biomarkers is critical to the success of targeted therapies such as AVB-500. Given AXL’s role in glucose homeostasis, one or more glycolytic intermediates may prove to be a useful biomarker to help predict sensitivity in patients, thus tailoring who would benefit from this treatment combination.

Citation Format: Shaina F. Bruce, Kevin Cho, Hollie Noia, Elena Lomonosova, Elizabeth Stock, Alyssa Oplt, Barbara Blachut, Mary M. Mullen, Lindsay M. Kuroki, Andrea R. Hagemann, Carolyn K. McCourt, Premal H. Thaker, Dineo Khabele, Matthew A. Powell, David G. Mutch, Leah P. Shriver, Gary J. Patti, Katherine C. Fuh. GAS6-AXL inhibition by AVB-500 overcomes resistance to paclitaxel in endometrial cancer by decreasing tumor cell glycolysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB081.

HER2 in endometrioid endometrial adenocarcinoma (E-EMCA): Defining incidence, molecular profiles, and outcomes

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Background: Immunohistochemistry (IHC) for HER2 in E-EMCA is not standard of care. We aimed to establish the correlation of HER2 transcript to IHC expression in the much more frequently tested uterine serous carcinoma (USC). We applied the threshold calculated in USC to E-EMCA and compared molecular and immune profiles among HER2+ and HER2- E-EMCA tumors, which may affect response to targeted therapy. Methods: 1462 E-EMCA tumors were analyzed using next-generation sequencing (592, NextSeq; WES, NovaSeq), WTS (NovaSeq) (Caris Life Sciences, Phoenix, AZ). PD-L1 was tested by IHC (SP142, >1%). Microsatellite instability (MSI) was tested by FA, IHC and NGS. TMB was measured by totaling somatic mutations per tumor (TMB-H: >10 mutations/MB). LOH cut-off was > 16%. HER2+ cut-off by WTS was determined by Receiver Operator Characteristic (ROC) analysis in USC tumors by comparing to HER2 IHC/CISH results using 2018 Breast Cancer ASCO/CAP Guidelines. Immune cell infiltrates were calculated by Quantiseq. Real world overall survival (OS) was extracted from insurance claims data and calculated using Kaplan-Meier survival curves for molecularly defined cohorts. Significance was determined using chi-square and Wilcoxon rank sum test and adjusted for multiple comparisons (q-value < 0.05), p < 0.05 but q > 0.05 was considered a trend. Results: We determined a cut-off of > 62.99 TPM for HER2+ with a sensitivity of 81.5%, specificity of 87.6% and AUC of 0.92 in Uterine Serous. When this cut-off is applied to E-EMCA, 76 of 1462 (5.2%) E-EMCA tumors were HER2+. HER2+ tumors had fewer mutations (mt) in PI3KR1, PTEN and CTNNB1 but higher mts in TP53 and more frequent LOH (q < 0.05). HER2+ tumors had a trend towards decreased MSI-H status (22.4% vs 39.1%; p = 0.003, q = 0.058) and TMB-H (25.4% vs 41.5%; p = 0.007, q = 0.084). MSS HER2+ E-EMCA had a similar mutational profile compared to all HER2+ tumors; MSI-H HER2+ E-EMCA had a trend towards higher DDR pathway gene mts compared to MSI-H HER2- EMCA tumors. HER2+ tumors had increased Dendritic cell (3.84% vs 2.97%) but decreased Neutrophil (2.66% vs 5.20%) and T-reg (1.38% vs 2.07%) infiltration (q < 0.01). HER2+ tumors had higher immune checkpoint gene expression of CD80, HAVCR2 and PDCD1LG2 (q < 0.01), and increased T-cell inflamed and MAPK activation score (q < 0.01). MSS HER2+ E-EMCA tumors had a similar immune profile when compared to all HER2+ tumors; MSI-H HER2+ E-EMCA tumors had increased Treg infiltration and MAPK activation score. Median OS was significantly worse for HER2+ pts compared to HER2- (64.3 vs. 23.6 months, HR: 1.93(1.32-2.80), p < 0.001). Conclusions: Using a WTS cutoff from USC, we found 5% of E-EMCA are HER2+ and showed distinct molecular and immune profile compared to HER2- tumors. HER2+ confers a worse OS compared to HER2- tumors. Furthermore, HER2+ tumors demonstrate an immune hot phenotype suggesting that immunotherapy may be a potential therapeutic option.

Impact of the COVID-19 pandemic on referral to and delivery of gynecologic oncology care

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The COVID-19 pandemic has significantly impacted gynecologic cancer care.

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Referrals to gynecologic oncology decreased in the early months of the pandemic.

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Referral time to gynecologic oncology evaluation was not impacted by the pandemic.

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Time to cancer treatment initiation decreased significantly during the pandemic.

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Disparities in time to cancer treatment initiation improving during the pandemic.

Objective

To evaluate the impact of the COVID-19 pandemic on referral to and delivery of gynecologic oncology care at a National Cancer Institute-designated Comprehensive Cancer Center.

Methods

We conducted a retrospective cohort study of patients referred for evaluation by a gynecologic oncologist at Washington University in St. Louis from October 2019 – February 2020 (pre-COVID-19), and April - August 2020 (COVID-19). The primary outcome, time from referral to evaluation by a gynecologic oncologist, was compared between the two time periods. Secondary outcomes included time from initial evaluation to treatment and delays/interruptions in care due to the pandemic. Sub-group analyses were performed on patients with a cancer diagnosis to evaluate the impact of COVID-19 on treatment decision making.

Results

884 patients were referred during the study period. Total referrals fell by 32% (526 to 358 patients, p < 0.001) and referrals for cancer fell by 18% (228 to 188 patients, p = 0.049). The pandemic did not impact time from referral to initial gynecologic oncology appointment overall (pre-COVID-19: 19.1 vs. COVID-19: 17.4 days, p = 0.315) or among patients with cancer (14.4 vs. 13.9 days, p = 0.662). Time from initial appointment to cancer treatment decreased by 9 days (34 days to 25 days, p = 0.001).

Conclusion

Referrals to gynecologic oncology decreased significantly during the early months of COVID-19. Though time from referral to evaluation was not impacted by the pandemic, time to treatment initiation decreased despite institutional changes related to COVID-19.

Inhibition of AXL and VEGF-A Has Improved Therapeutic Efficacy in Uterine Serous Cancer

Endometrial cancer remains the most prevalent gynecologic cancer with continued rising incidence. A less common form of this cancer is uterine serous cancer, which represents 10% of endometrial cancer cases. However, this is the most aggressive cancer. The objective was to assess whether inhibiting the receptor tyrosine kinase AXL with AVB-500 in combination with bevacizumab would improve response in uterine serous cancer. To prove this, we conducted multiple angiogenesis assays including tube formation assays and angiogenesis invasion assays. In addition, we utilized mouse models with multiple cells lines and subsequently analyzed harvested tissue through immunohistochemistry CD31 staining to assess microvessel density. The combination treatment arms demonstrated decreased angiogenic potential in each assay. In addition, intraperitoneal mouse models demonstrated a significant decrease in tumor burden in two cell lines. The combination of AVB-500 and bevacizumab reduced tumor burden in vivo and reduced morphogenesis and migration in vitro which are vital to the process of angiogenesis.

Implementation of an enhanced recovery protocol in gynecologic oncology

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Enhanced recovery in gynecologic oncology decreased narcotic usage.

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Shorter length of hospital stay was also observed in the ERAS cohort.

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ERAS produced early return of bowel function.

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The ERAS cohort received less perioperative blood transfusions.

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A compliance analysis is integral to successful implementation of ERAS.

Enhanced Recovery after Surgery (ERAS) is an evidence-based approach that aims to reduce narcotic use and maintain anabolic balance to enable full functional recovery. Our primary aim was to determine the effect of ERAS on narcotic usage among patients who underwent exploratory laparotomy by gynecologic oncologists. We characterized its effect on length of stay, intraoperative blood transfusions, bowel function, 30-day readmissions, and postoperative complications. A retrospective cohort study was performed at Abington Hospital-Jefferson Health in gynecologic oncology. Women who underwent an exploratory laparotomy from 2011 to 2016 for both benign and malignant etiologies were included before and after implementation of our ERAS protocol. Patients who underwent a bowel resection were excluded. A total of 724 patients were included: 360 in the non-ERAS and 364 in the ERAS cohort. An overall reduction in narcotic usage, measured as oral morphine milliequivalents (MMEs) was observed in the ERAS relative to the non-ERAS group, during the entire hospital stay (MME 34 versus 68, p < 0.001 and within 72 h postoperatively (MME 34 versus 60, p < 0.005). A shorter length of stay and earlier return of bowel function were also observed in the ERAS group. No differences in 30-day readmissions (p = 0.967) or postoperative complications (p = 0.328) were observed. This study demonstrated the benefits of ERAS in Gynecologic Oncology. A significant reduction of postoperative narcotic use, earlier return of bowel function and a shorter postoperative hospital stay was seen in the ERAS compared to traditional perioperative care.

Implementation of an abdominal closure bundle to reduce surgical site infection in patients on a gynecologic oncology service undergoing exploratory laparotomy

OBJECTIVE

Surgical site infections (SSI) are associated with increased morbidity, mortality, and healthcare costs. This study investigated whether implementation of an abdominal closure bundle reduces surgical site infection rates. We aimed to identify sub-populations that would benefit the most from this intervention.

METHODS

We conducted a retrospective cohort study of all patients that underwent exploratory laparotomy by a Gynecologic Oncologist from January 1, 2011 to April 1, 2017. The abdominal closure bundle was implemented on May 6, 2014. SSI rates were assessed overall and within subgroups.

RESULTS

875 patients were included in the analysis. Overall, SSI rate was reduced, albeit not significantly, from 48/471 (10.2%) to 32/404 (7.9%) (p=0.148) with implementation of the closing bundle. In patients that underwent a tumor debulking procedure, SSI was noted in 36/277 (13.0%) in the pre-bundle group and 14/208 (6.7%) in the post-bundle cohort (p=0.017). In patients with malignant pathology, the pre-bundle cohort had an SSI rate of 38/282 (13.5%), which reduced to 18/215 (8.4%) in the post-bundle group (p=0.049). In patients with FIGO stage III or IV disease, the SSI rate was reduced from 21/114 (18.4%) to 8/87 (8.4%) with implantation of the closure bundle (p=0.028). In patients with intra-operative ascites, SSI rate decreased from 19/119 (15.9%) pre-bundle to 4/104 (3.8%) in the post-bundle group (p=0.002).

CONCLUSIONS

Implementation of an abdominal closure bundle was not associated with a significant reduction in overall SSI rate. However, multiple subpopulations associated with advanced gynecologic cancer benefited from this intervention.