Mapping three-dimensional intratumor proteomic heterogeneity in uterine serous carcinoma by multiregion microsampling.

BACKGROUND: Although uterine serous carcinoma (USC) represents a small proportion of all uterine cancer cases, patients with this aggressive subtype typically have high rates of chemotherapy resistance and disease recurrence that collectively result in a disproportionately high death rate. The goal of this study was to provide a deeper view of the tumor microenvironment of this poorly characterized uterine cancer variant through multi-region microsampling and quantitative proteomics. METHODS: Tumor epithelium, tumor-involved stroma, and whole "bulk" tissue were harvested by laser microdissection (LMD) from spatially resolved levels from nine USC patient tumor specimens and underwent proteomic analysis by mass spectrometry and reverse phase protein arrays, as well as transcriptomic analysis by RNA-sequencing for one patient's tumor. RESULTS: LMD enriched cell subpopulations demonstrated varying degrees of relatedness, indicating substantial intratumor heterogeneity emphasizing the necessity for enrichment of cellular subpopulations prior to molecular analysis. Known prognostic biomarkers were quantified with stable levels in both LMD enriched tumor and stroma, which were shown to be highly variable in bulk tissue. These USC data were further used in a comparative analysis with a data generated from another serous gynecologic malignancy, high grade serous ovarian carcinoma, and have been added to our publicly available data analysis tool, the Heterogeneity Analysis Portal ( https://lmdomics.org/ ). CONCLUSIONS: Here we identified extensive three-dimensional heterogeneity within the USC tumor microenvironment, with disease-relevant biomarkers present in both the tumor and the stroma. These data underscore the critical need for upfront enrichment of cellular subpopulations from tissue specimens for spatial proteogenomic analysis.

The comparison of pure uterine serous carcinoma and mixed tumor with serous component: a single-institution review of 91 cases.

BACKGROUND: Pure uterine serous carcinoma (p-USC) and mixed tumors with serous component (m-USC) are aggressive subtypes of endometrial cancer associated with high mortality rates. This retrospective study aimed to compare clinicopathologic features and outcomes of p-USC and m-USC in a single center. METHODS: This study retrospectively reviewed patients diagnosed with USC at Peking University People's Hospital between 2008 and 2022. T-tests and chi-square tests were used to compare clinicopathological characteristics between p-USC and m-USC. Kaplan-Meier survival curve and Cox regression analysis were used to analyze the impact of clinical and pathological variables on OS and PFS. RESULTS: Among the 91 patients who underwent surgery, 65.9% (n = 60) were p-USC, and 34.1% (n = 31) were m-USC. Patients with p-USC had earlier menopause (P = 0.0217), a lower rate of progesterone receptor(PR) expression (P < 0.001), and were more likely to have positive peritoneal cytology (P = 0.0464). After a median follow-up time of 40 months, 28 (46.7%) p-USC and 9 (29%) m-USC patients had progression disease, 18 (30%) and 8 (25.8%) patients died of their disease. 5-year PFSR were 51.2% and 75.3%, respectively, and 5-year OS rates were 66% and 67.4%. Kaplan-Meier survival analysis showed that p-USC was more likely to relapse than m-USC (P = 0.034), but there was no significant difference in OS. Cox regression analysis showed that lymph node metastasis and surgical approach were risk factors for OS, and myoinvasion depth ≥ 1/2 was an independent risk factor for PFS. CONCLUSIONS: p-USC was more likely to relapse than m-USC, but there was no significant difference in OS between the two subtypes.

High-dose ascorbate exerts anti-tumor activities and improves inhibitory effect of carboplatin through the pro-oxidant function pathway in uterine serous carcinoma cell lines.

OBJECTIVE: Uterine serous carcinoma is a highly aggressive non-endometrioid subtype of endometrial cancer with poor survival rates overall, creating a strong need for new therapeutic strategies to improve outcomes. High-dose ascorbate (vitamin C) has been shown to inhibit cell proliferation and tumor growth in multiple preclinical models and has shown promising anti-tumor activity in combination with chemotherapy, with a favorable safety profile. We aimed to study the anti-tumor effects of ascorbate and its synergistic effect with carboplatin on uterine serous carcinoma cells. METHODS: Cell proliferation was evaluated by MTT and colony formation assays in ARK1, ARK2 and SPEC2 cells. Cellular stress, antioxidant ability, cleaved caspase 3 activity and adhesion were measured by ELISA assays. Cell cycle was detected by Cellometer. Invasion was measured using a wound healing assay. Changes in protein expression were determined by Western immunoblotting. RESULTS: High-dose ascorbate significantly inhibited cell proliferation, caused cell cycle arrest, induced cellular stress, and apoptosis, increased DNA damage, and suppressed cell invasion in ARK1 and SPEC2 cells. Treatment of both cells with 1 mM N-acetylcysteine reversed ascorbate-induced apoptosis and inhibition of cell proliferation. The combination of ascorbate and carboplatin produced significant synergistic effects in inhibiting cell proliferation and invasion, inducing cellular stress, causing DNA damage, and enhancing cleaved caspase 3 levels compared to each compound alone in both cells. CONCLUSIONS: Ascorbate has potent antitumor activity and acts synergistically with carboplatin through its pro-oxidant effects. Clinical trials of ascorbate combined with carboplatin as adjuvant treatment of uterine serous carcinoma are worth exploring.

Assessment of the differences in oncologic outcomes between patients with high-grade serous ovarian carcinoma and uterine serous carcinoma.

AIM: To evaluate whether the recurrence rates, recurrence patterns, and survival outcomes differed according to the primary site of the tumor in patients with high-grade serous ovarian carcinoma (HGSOC) and uterine serous carcinoma (USC). METHODS: The population of this multicenter retrospective study consisted of patients who had USC or HGSOC. Progression-free survival (PFS) and disease-specific survival (DSS) estimates were determined using the Kaplan-Meier method. Survival curves were compared using the log-rank test. RESULTS: The study cohort consisted of 247 patients with HGSOC and 34 with USC. Recurrence developed in 118 (51.1%) in the HGSOC group and 14 (42.4%) in the USC group (p = 0.352). The median time to recurrence was 23.5 (range, 4-144) and 17 (range, 4-43) months in the HGSOC and USC groups, respectively (p = 0.055). The 3-year PFS was 52% in the HGSOC group and 47% in the USC group (p = 0.450). Additionally, 3-year DSS was 92% and 82% in the HGSOC and USC groups, respectively (p = 0.060). CONCLUSIONS: HGSOC and USC are aggressive tumors with high recurrence and mortality rates in advanced stages. These two carcinomas, which are similar in molecular features and clinical management, may also have similar recurrence patterns, disease failure, and survival rates.

Ultrasonographic evaluation of endometrial stripe thickness is insufficient to rule out uterine serous carcinoma.

PURPOSE: Uterine serous carcinoma (USC) is a rare endometrial cancer representing less than 10% of uterine cancers but contributing to up to 50% of the mortality. Delay in diagnosis with this high-grade histology can have significant clinical impact. USC is known to arise in a background of endometrial atrophy. We investigated endometrial stripe (EMS) thickness in USC to evaluate current guidelines for postmenopausal bleeding in the context of this histology. METHODS: Retrospective chart review was conducted using ICD-9 and ICD-10 codes over an 18-year period. We included 139 patients with USC and compared characteristics of patients with EMS ≤ 4 mm and EMS > 4 mm. Chi-square or Fisher's exact tests were used to compare proportions and two-tailed t-tests to compare means. A p-value of < 0.05 was considered statistically significant. RESULTS: Most patients were white, obese, and multiparous. Thirty-two (23%) had an EMS ≤ 4 mm; 107 (77%) had an EMS > 4 mm. There were no statistically significant differences in age at diagnosis or presenting symptoms between groups, and postmenopausal bleeding was the most common symptom in each group. CONCLUSION: Nearly 25% of patients with USC initially evaluated with transvaginal ultrasound were found to have an EMS ≤ 4 mm. If transvaginal ultrasound is used to triage these patients, one in four women will potentially experience a delay in diagnosis that may impact their prognosis.

Laparoscopy with or without robotic assistance does not negatively impact long-term oncologic outcomes in patients with uterine serous carcinoma.

OBJECTIVES: We sought to compare outcomes between minimally invasive surgery (MIS) and laparotomy in patients with clinical stage I uterine serous carcinoma (USC). METHODS: Patients who underwent surgery for newly diagnosed USC between 11/1/1993 and 12/31/2017 were retrospectively identified and assigned to either the MIS cohort or the laparotomy cohort. Patients with conversion to laparotomy were analyzed with the MIS cohort. Chi-square and Mann-Whitney tests were used to compare categorical and continuous variables, respectively. Kaplan-Meier curves were used to estimate survival and compared using the log-rank test. RESULTS: In total, 391 patients met inclusion criteria; 242 underwent MIS (35% non-robotic and 65% robotic-assisted laparoscopies) and 149 underwent laparotomy. Age, BMI, stage, and washings status did not differ between cohorts. Patients who underwent MIS were less likely to have lymphovascular space invasion (LVSI; 35.1% vs 48.3%), had fewer nodes removed (median, 9 vs 15), and lower rates of paraaortic nodal dissection (44.6% vs 65.1%). Rates of adjuvant therapy did not differ between cohorts. Median follow-up times were 63.0 months (MIS cohort) vs 71.0 months (laparotomy cohort; P = .04). Five-year PFS rates were 58.7% (MIS) vs 59.8% (laparotomy; P = .1). Five-year OS rates were 65.2% (MIS) compared to 63.5% (laparotomy; P = .2). On multivariable analysis, higher stage, deep myometrial invasion, and positive washings were associated with decreased PFS. Age ≥ 65 years, higher stage, LVSI, and positive washings were associated with shorter OS. CONCLUSIONS: MIS does not compromise outcomes in patients with newly diagnosed USC and should be offered to these patients to minimize surgical morbidity.

Comparison of clinical characteristics and prognosis in endometrial carcinoma with different pathological types: a retrospective population-based study.

BACKGROUND: Endometrial carcinoma (EC) is the second most common gynecological malignancy, and the differences between different pathological types are not entirely clear. Here, we retrospectively collected eligible EC patients to explore their differences regarding clinical characteristics and prognosis. METHODS: Five hundred seventy EC patients from the First Affiliated Hospital of Zhengzhou University were included. Prognostic factors were measured using the univariate/multivariate Cox models. Overall survival (OS) and progression-free survival (PFS) were the primary and secondary endpoints, respectively. RESULTS: In total, 396 patients with uterine endometrioid carcinoma (UEC), 106 patients with uterine serous carcinoma (USC), 34 patients with uterine mixed carcinoma (UMC), and 34 patients with uterine clear cell carcinoma (UCCC) were included. Comparison of baseline characteristics revealed patients diagnosed with UEC were younger, had more early clinical stage, and had lower incidence of menopause and lymph node metastasis. Compared to UEC, other pathological EC obtained more unfavorable OS (UCCC: HR = 12.944, 95%CI = 4.231-39.599, P < 0.001; USC: HR = 5.958, 95%CI = 2.404-14.765, P < 0.001; UMC: HR = 1.777, 95%CI = 0.209-15.114, P = 0.599) and PFS (UCCC: HR = 8.696, 95%CI = 1.972-38.354, P = 0.004; USC: HR = 4.131, 95%CI = 1.243-13.729, P = 0.021; UMC: HR = 5.356, 95%CI = 0.935-30.692, P = 0.060). Compared with UEC patients, the OS of UCCC patients in stage I-II and USC patients in stage III-IV were significantly worse, while UMC patients in stage I-II favored poorer PFS. The OS of UCCC patients receiving no postoperative adjuvant therapy or chemotherapy alone were significantly worse. CONCLUSIONS: The baseline characteristics of UEC and other rare EC types varied greatly, and the prognostic significance of different pathological types on EC patients depended on clinical tumor stages and therapeutic options.

Distinct histological and clinical features associated with pure uterine serous carcinoma: A single institution experience.

AIM: To ascertain the clinicopathological features, survival, and prognostic factors of pure uterine serous carcinoma (pUSC) and compare its clinicopathological characteristics with those of serous-like grade-3 endometrioid endometrial carcinoma (G3-EEC). METHOD: Consecutive patients with pUSC and p53 abnormal (p53abn) G3-EEC were retrospectively selected between 2014 and 2022. Histological and immunohistochemical features were reviewed, clinical information was collected, and survival analyses were performed. RESULTS: Eighty-five pUSC patients (mean age: 61.6 years) were included. Histologically, pUSC showed a predominantly glandular growth pattern (80.0 %) with high-grade nuclear atypia and obvious nucleoli and 53 cases showed admixtures of architectural patterns. The p53 aberrant expression rate was 98.8 %. 41.5 %, 53.7 %, and 67.5 % of cases were classified as negative for ER, PR, and WT1, respectively. Six (12.3 %) of 49 cases had a HER2 score of 3+ by immunohistochemistry (IHC). The overall survival and progression-free survival rates were 72.9 % and 63.5 %, respectively. Advanced stage, no adjuvant therapy, and lymph node metastasis were independent risk factors for poor survival in pUSC. Twenty-five p53abn G3-EEC patients were assessed. Women with p53abn G3-EEC were on average, younger than those with pUSC (53.4 vs. 61.6 years, P < 0.001). Papillary structures were observed more commonly in pUSC (16 % vs. 36.5 %, P = 0.042). Positive PR expression was significantly associated with p53abn G3-EEC (P = 0.009). Survival did not differ significantly between the subgroups in univariate and multivariate analyses. CONCLUSION: In this contemporary series, we affirm the suboptimal prognosis associated with pUSC, and that the survival associated with pUSC and p53abn G3-EEC are not significantly different. pUSC and p53abn G3-EEC have distinct morphological and immunohistochemical characteristics.

Monitoring Treatment Response, Early Recurrence, and Survival in Uterine Serous Carcinoma and Carcinosarcoma Patients Using Personalized Circulating Tumor DNA Biomarkers.

Uterine serous carcinoma (USC) and carcinosarcomas (CSs) are rare, highly aggressive variants of endometrial cancer. No reliable tumor biomarkers are currently available to guide response to treatment or detection of early recurrence in USC/CS patients. Circulating tumor DNA (ctDNA) identified using ultrasensitive technology such as droplet digital polymerase chain reaction (ddPCR) may represent a novel platform for the identification of occult disease. We explored the use of personalized ctDNA markers for monitoring USC and CS patients. Tumor and plasma samples from USC/CS patients were collected at the time of surgery and/or during the treatment course for assessment of tumor-specific somatic structural variants (SSVs) by a clinical-grade next-generation sequencing (NGS) platform (i.e., Foundation Medicine) and a droplet digital PCR instrument (Raindance, ddPCR). The level of ctDNA was quantified by droplet digital PCR in plasma samples and correlated to clinical findings, including CA-125 serum and/or computed tomography (CT) scanning results. The genomic-profiling-based assay identified mutated "driver" target genes for ctDNA analysis in all USC/CS patients. In multiple patients, longitudinal ctDNA testing was able to detect the presence of cancer cells before the recurrent tumor was clinically detectable by either CA-125 or CT scanning. Persistent undetectable levels of ctDNA following initial treatment were associated with prolonged progression-free and overall survival. In a USC patient, CA-125 and TP53 mutations but not PIK3CA mutations become undetectable in the plasma at the time of recurrence, suggesting that more than one customized probe should be used for monitoring ctDNA. Longitudinal ctDNA testing using tumor-informed assays may identify the presence of residual tumors, predict responses to treatment, and identify early recurrences in USC/CS patients. Recognition of disease persistence and/or recurrence through ctDNA surveillance may allow earlier treatment of recurrent disease and has the potential to change clinical practice in the management of USC and CS patients. CtDNA validation studies in USC/CS patients prospectively enrolled in treatment trials are warranted.

Neoadjuvant chemotherapy in patients with stage IVB uterine serous carcinoma: a Turkish multicentric study.

The aim of this study was to evaluate the prognostic factors for and determine the effect of neoadjuvant chemotherapy (NACT) on oncologic outcome in stage IVB pure serous endometrial carcinoma patients who received taxane and platinum. Forty-two patients with 2009 International Federation of Gynecology and Obstetrics (FIGO) stage IVB uterine serous carcinoma were enrolled from six gynecologic oncology centers and a study group was created. The study group had a 2-year disease-free survival (DFS) of 32% and 2-year disease-specific survival (DSS) of 73%. On univariate analysis; lymphadenectomy (not performed vs. performed), paraaortic lymph node metastasis (positive vs. negative) and number of metastatic lymph node count (≤5 vs. >5) were found to have statistical significance for DFS (p < 0.001, p = 0.026 and p = 0.044, respectively). Adnexal metastasis (positive vs. negative) and type of cytoreductive surgery (maximal vs. optimal and suboptimal) had statistical significance for DSS (p = 0.041 and p = 0.015, respectively). Receiving NACT did not affect DFS and DSS in stage IVB uterine serous carcinoma patients. As our sample size was small, precise conclusions could not be made for suggesting the use of NACT in advanced stage uterine serous carcinoma. For more accurate results, more randomized controlled studies are needed in this patient group.IMPACT STATEMENTWhat is already known on this subject? Endometrial carcinoma is the most common type of gynecologic tract malignancies and usually it is diagnosed at early stages. Although the favorable prognosis, uterine serous carcinoma (USC), one of the rarest subtypes, has a poorer prognosis when compared to other histological subtypes. USC has a propensity to spread beyond pelvis. Due to this aggressive behavior, surgical intervention could not be feasible in advanced stage disease.What do the results of this study add? Our study evaluated the prognostic factors that affect survival in advanced stage USC patients. Also we investigated that neoadjuvant chemotherapy (NACT) could improve oncologic outcomes. Performing lymphadenectomy, presence of paraaortic lymph node and adnexal metastasis, number of metastatic lymph nodes and type of cytoreductive surgery improved survival in advanced stage USC patients. However, NACT did not have a statistical significance as a predictor for disease-specific survival (DSS) and disease-free survival (DFS).What are the implications of these findings for clinical practice and/or further research? Maximal surgical effort should be performed in advanced stage USC according to our results. On the other hand, NACT had no impact on DSS and DFS rates. For this reason, we could not be able to suggest the routine use of NACT in advanced stage USC. But more randomized controlled trials are warranted for confirmation of our results.

Adjuvant therapy in women with early stage uterine serous carcinoma: A multi-institutional study.

OBJECTIVE: Uterine serous carcinoma is a rare but aggressive subtype of endometrial adenocarcinoma. Our objective was to compare adjuvant treatment strategies for patients with early stage uterine serous carcinoma. METHODS: This multi-institutional, retrospective cohort study evaluated patients with early stage uterine serous carcinoma. Patients with FIGO Stage IA-II disease after surgery, whose tumors had serous or any mixed serous/non-serous histology were included. Patients with carcinosarcoma were excluded. Clinical data were abstracted from local medical records. Summary statistics, Fisher's exact, and Kruskal-Wallis tests were used to analyze demographic and clinical characteristics. Univariable and multivariable analyses were performed for recurrence-free and overall survival. RESULTS: There were 737 patients included. Most patients had Stage IA disease (75%), 49% of which had no myometrial invasion. Only 164 (24%) tumors had lymphatic/vascular space invasion. Adjuvant treatment varied: 22% received no adjuvant therapy, 17% had chemotherapy alone, 19% had cuff brachytherapy, 35% had cuff brachytherapy with chemotherapy, and 6% underwent pelvic radiation. Adjuvant treatment was significantly associated with a decreased risk of recurrence (p = 0.04). Compared with no adjuvant therapy, patients who received brachytherapy or brachytherapy/chemotherapy had improved recurrence-free survival (HR 0.59, 95% CI 0.40-0.86; HR 0.65, 95% CI 0.49-0.88, respectively) and overall survival (HR 0.53, 95% CI 0.35-0.79; HR 0.49, 95% CI 0.35-0.69, respectively). Improved survival with brachytherapy and brachytherapy/chemotherapy persisted on multivariable analyses. Chemotherapy alone was also associated with improved overall survival compared with no adjuvant treatment (HR 0.55, 95% CI 0.37-0.81). CONCLUSIONS: Adjuvant therapy was associated with a decreased risk of recurrence relative to observation alone. Adjuvant cuff brachytherapy with and without chemotherapy was associated with improved survival outcomes in patients with early stage uterine serous carcinoma.

Synergistic activity of neratinib in combination with olaparib in uterine serous carcinoma overexpressing HER2/neu.

INTRODUCTION: Uterine serous carcinoma (USC) is an aggressive variant of endometrial cancer with a poor prognosis. Approximately 30% of USC overexpress HER2/neu, a recognized target for trastuzumab in advanced/recurrent HER2/neu-positive USC. We evaluated the efficacy of the pan-c-erb inhibitor neratinib and the poly (ADP-ribose)-polymerase (PARP) inhibitor olaparib as single agents and in combination against USC cell lines and xenografts. METHODS: In-vitro cell-viability assays with olaparib, neratinib, and olaparib/neratinib were assessed using flow-cytometry based assays against a panel of USC cell lines with high and low HER2/neu expression. Homologous recombination deficiency (HRD) signatures were evaluated as described by Alexandrov et al. (Nature;2020;578:94-101) while downstream signaling affected by neratinib/olaparib exposure was assessed with immunoblotting. Efficacy of single- versus dual-agent inhibition was evaluated in-vivo using two USC-xenografts with 3+ HER2/neu expression. RESULTS: Neratinib was more potent than olaparib in suppression of in-vitro growth of HER2/neu 3+ cell lines (ARK1: p = 0.0047; ARK2: p = 0.0428) while no difference was noted against HER2/neu 1+ tumors (ARK4). Importantly, the combination of olaparib with neratinib synergistically improved tumor suppression compared to either single-agent in vitro. USC cells exposed to olaparib upregulated HER2/neu expression, while neratinib treatment increased PARP activity (ARK1: p < 0.0001; ARK2: p < 0.0001). Single-agent neratinib transiently inhibited in vivo growth of USC xenografts harboring HER2/neu gene amplification (ARK1: p < 0.05; ARK2: p < 0.05). In contrast, the combination of the two inhibitors caused a stronger and durable growth inhibition in both USC xenografts (ARK1: p < 0.05; ARK2: p < 0.05). CONCLUSION: The combination of olaparib and neratinib is active and synergistic against primary HER2/neu + USC. This combination may represent a novel therapeutic option for USC patients with HER2/neu+, homologous recombination-proficient tumors resistant to chemotherapy.

Conditional estimates for uterine serous cancer: Tools for survivorship counseling and planning.

OBJECTIVES: Develop conditional survival and risk-assessment estimates for uterine serous carcinoma (USC) overall and stratified by stage as tools for annual survivorship counseling and care planning. METHODS: Patients in the National Cancer Data Base diagnosed between 2004 and 2014 with stage I-IV USC were eligible. Individuals missing stage or survival data or with multiple malignancies were excluded. Five-year conditional survival was estimated using the stage-stratified Kaplan-Meier method annually during follow-up. A standardized mortality ratio (SMR) estimated the proportion of observed to expected deaths in the U.S. adjusted for year, age, and race. The relationships between prognostic factors and survival were studied using multivariate Cox modeling at diagnosis and conditioned on surviving 5-years. RESULTS: There were 14,575 participants, including 43% with stage I, 8% with stage II, 29% with stage III, and 20% with stage IV USC. Five-year survival at diagnosis vs. after surviving 5-years was 52% vs. 75% overall, 77% vs. 81% for stage I, 57% vs. 72% for stage II, 40% vs. 66% for stage III, and 17% vs. 60% for stage IV USC, respectively (P < 0.0001). Incremental improvements in 5-year conditional survival and reductions in SMR tracked with annual follow-up and higher stage. The adjusted risk of death at diagnosis vs. after surviving 5-years was 1.15 vs. 1.40 per 5-year increase of age, 1.26 vs. 1.68 for Medicaid insurance, 3.92 vs. 2.48 for stage III disease, and 6.65 vs. 2.79 for stage IV disease, respectively (P < 0.0001). CONCLUSION: In USC, the evolution of conditional survival permits annual reassessments of prognosis to tailor survivorship counseling and care planning.

HER2 in Uterine Serous Carcinoma: Testing platforms and implications for targeted therapy.

OBJECTIVE: HER2 is an important prognostic and therapeutic target in uterine serous carcinoma (USC). Optimal HER2 testing platforms have not been defined and guidelines for testing have changed over time. Our objective is to assess the concordance of HER2 positivity based on chromogenic in situ hybridization (CISH), immunohistochemistry (IHC), and next generation sequencing (NGS) and to determine the rate of downstream mutations that may affect response to HER2 directed therapy. METHODS: Utilizing the Caris tumor registry, 2192 USC tumors were identified and analyzed using NGS (NextSeq, 592 Genes and WES, NovaSEQ), IHC, and CISH. PD-L1 expression was tested by IHC. Microsatellite instability was tested by fragment analysis, IHC, and NGS. Tumor mutational burden (TMB) was measured by totaling somatic mutations per tumor. HER2 positivity through IHC and CISH was determined based on 2007 and 2018 ASCO/CAP HER2 breast cancer guidelines. RESULTS: There was a higher rate of HER2 positivity by IHC when using the 2018 guidelines compared to the 2007 guidelines (16.3% vs 12.3%). Concordance between IHC and CISH was 98.9%. ERBB2 amplification was identified by NGS in 10.5% of tumors. Compared to CISH results, this corresponds to a concordance rate of 91.6% and a positive predictive value (PPV) of 60.3%. Single gene alterations in HER2 amplified tumors that may implicate HER2 therapy resistance included PI3K (33.1%), KRAS (2.5%), and PTEN (1.3%). CONCLUSIONS: There was high concordance between HER2 positivity based on CISH and IHC. Rate of HER2 positivity is the lowest by NGS. Ultimately these testing platforms need to be validated by response to targeted therapy.

Real-world outcomes in patients with advanced endometrial cancer: A retrospective cohort study of US electronic health records.

OBJECTIVES: To characterize clinical outcomes of women with advanced/recurrent endometrial cancer (AEC) in routine practice using electronic health records from a real-world database. METHODS: Adult women diagnosed with AEC (stage III/IV, or early stage with locoregional/distant recurrence) between January 1, 2013 and September 30, 2020, inclusive, were eligible provided they received platinum-based chemotherapy at any time following diagnosis and had ≥2 clinical visits. Follow-up was from initiation of systemic treatment after advanced diagnosis (index) until March 30, 2021, last available follow-up, or death, whichever occurred first. Outcomes, by histological subtype, included Kaplan-Meier estimates of overall survival (OS) and time to first subsequent therapy or death (TFST). RESULTS: Of the 2202 women with AEC, most were treated in a community setting (82.7%) and presented with stage III/IV disease at initial diagnosis (74.0%). The proportion with endometrioid carcinoma, uterine serous carcinoma (USC), and other AEC subtypes was 59.8%, 25.0%, and 15.2%, respectively. The most common first systemic treatment following advanced/recurrent diagnosis was platinum-based combination chemotherapy (82.0%). Median OS (95% CI) from initiation of first systemic treatment was shorter with USC (31.3 [27.7-34.3] months) and other AECs (29.4 [21.4-43.9] months) versus endometrioid carcinoma (70.8 [60.5-83.2] months). Similar results were observed for TFST. Black/African American women had worse OS and TFST than white women. CONCLUSIONS: Women with AEC had poor survival outcomes, demonstrating the requirement for more effective therapies. To our knowledge, this is the most comprehensive evaluation of contemporary treatment of AEC delivered in a community setting to date.

Targeted Therapies in the Treatment of Uterine Serous Carcinoma.

OPINION STATEMENT: Despite the dismal prognosis of uterine serous carcinoma (USC), recent advances in molecular classification and targeted treatments have demonstrated improvements in survival outcomes for patients both in the upfront and recurrent treatment settings. After appropriate surgical staging and surgical cytoreduction as indicated, correct pathologic and molecular classification of USC is important to provide the most appropriate systemic adjuvant treatment. HER2-targeted agents are one of the most important advances in the treatment of USC in decades. Thus, for HER2-positive tumors, the addition of trastuzumab to conventional chemotherapy is indicated in those with advanced stage and/or recurrent disease. Treatment with pembrolizumab and lenvatinib suggests a 50% response rate in women with recurrent disease which serves as a promising targeted treatment strategy. Overall, emerging targeted therapeutic options with antibody-drug conjugates (i.e. targeting HER2, folic acid receptor alpha, or Trop-2), combinations of immunotherapies and tyrosine kinase inhibitors, PARP inhibitors, WEE1 inhibitors, and AKT inhibitors shed further promise in advancements of effective disease-modifying treatments for this unmet medical need for patients with USC. Several trials evaluating these targeted agents are ongoing, and those results are eagerly awaited. As such, enrollment of patients in clinical trials is highly recommended as it will provide patients with a higher level of personalized cancer care.

A Durable Response to Pembrolizumab in a Patient with Uterine Serous Carcinoma and Lynch Syndrome due to the MSH6 Germline Mutation.

Pembrolizumab, a programmed death 1 ligand (PD-1) checkpoint inhibitor, has elicited responses in mismatch repair (MMR)-deficient advanced solid tumors, leading to its agnostic approval by the US Food and Drug Administration in 2017 when no other therapeutic options are available. However, there are still insufficient data on the response to checkpoint inhibitors in advanced endometrial cancer related to Lynch syndrome (LS) and, specifically, in uterine serous carcinoma, which is uncommon in LS. Here we report a case of metastatic uterine serous carcinoma due to a germline MSH6 mutation (Lynch syndrome) that was discovered because of a patient's tumor MMR deficiency. The patient was started on first-line pembrolizumab in 2018 and sustained a partial response. She remains asymptomatic and progression free for more than 2 years. Tumor sequencing showed a high mutational burden and an upstream somatic mutation in the same gene, p.F1088fs. Immunohistochemical staining was negative for PD-L1 expression. We discuss clinical characteristics of the patient, molecular features of her tumor, and the mechanism of her tumor response. We also discuss the duration of immunotherapy in her case. Our case demonstrated a partial response and a long-term remission from the frontline single-agent pembrolizumab in a woman with metastatic uterine serous carcinoma and Lynch syndrome due to a germline MSH6 gene mutation. Our experience suggests a potential significant clinical benefit of checkpoint inhibitors used as single agents early on in the treatment of MMR-deficient/high microsatellite instability/hypermutated uterine cancers in women with Lynch syndrome. KEY POINTS: Even though checkpoint inhibitors are effective in mismatch repair-deficient endometrial cancer, it is unknown whether the response to them differs between women with endometrial cancer due to germline mutations in a mismatch repair gene (Lynch syndrome) and women with sporadic endometrial cancer. In our case, a patient with Lynch syndrome and recurrent mismatch repair-deficient serous endometrial cancer achieved a durable remission on the first-line therapy with the checkpoint inhibitor pembrolizumab and remains progression free after more than 2 years. Based on our observation and the data, suggesting the stronger immune activation in women with Lynch syndrome-associated endometrial cancer, we propose to use checkpoint inhibitor monotherapy early in the course of their treatment and stratify patients for the presence of Lynch syndrome in clinical trials.

A 4-gene signature predicts prognosis of uterine serous carcinoma.

BACKGROUND: Uterine serous carcinoma (USC) is an aggressive type of endometrial cancer that accounts for up to 40% of endometrial cancer deaths, creating an urgent need for prognostic biomarkers. METHODS: USC RNA-Seq data and corresponding patients' clinical records were obtained from The Cancer Genome Atlas and Genotype-Tissue Expression datasets. Univariate cox, Lasso, and Multivariate cox regression analyses were conducted to forge a prognostic signature. Multivariable and univariable cox regression analysis and ROC curve evaluated the prediction efficiency both in the training and testing sets. RESULTS: We uncovered 1385 genes dysregulated in 110 cases of USC tissue relative to 113 cases of normal uterine tissue. Functional enrichment analysis of these genes revealed the involvement of various cancer-related pathways in USC. A novel 4-gene signature (KRT23, CXCL1, SOX9 and ABCA10) of USC prognosis was finally forged by serial regression analyses. Overall patient survival (OS) and recurrence-free survival (RFS) were significantly lower in the high-risk group relative to the low-risk group in both the training and testing sets. The area under the ROC curve of the 4-gene signature was highest among clinicopathological features in predicting OS and RFS. The 4-gene signature was found to be an independent prognostic indicator in USC and was a superior predictor of OS in early stage of USC. CONCLUSIONS: Our findings highlight the potential of the 4-gene signature as a guide for personalized USC treatment.

Trastuzumab with carboplatin/paclitaxel for treatment of advanced stage and recurrent uterine papillary serous carcinoma: A cost-effectiveness analysis.

OBJECTIVE: Uterine papillary serous carcinoma (UPSC) is a variant of endometrial cancer that is aggressive and associated with poor outcomes. We sought to evaluate the cost effectiveness of carboplatin/paclitaxel alone versus carboplatin/paclitaxel with trastuzumab among patients with Her2/neu-positive advanced or recurrent UPSC. METHODS: We designed a Markov model in TreeAge Pro 2019 software to simulate management of a theoretical cohort of 4000 patients with Her2/neu-positive advanced or recurrent uterine papillary serous carcinoma (UPSC) followed for four years. In the carboplatin/paclitaxel with trastuzumab strategy, we included the cost of testing for Her2/neu status. We obtained all model inputs from the literature and a societal perspective was assumed. Outcomes included progression-free survival, progression, UPSC-specific mortality, cost, and quality-adjusted life years (QALYs). The intervention was considered cost effective if the incremental cost-effectiveness ratio (ICER) was below the willingness-to-pay threshold of $100,000 per QALY. Sensitivity analyses were used to determine the robustness of the results. RESULTS: In our theoretical cohort of 4000 women, treatment with the addition of trastuzumab resulted in 637 fewer deaths and 627 fewer cases of progression compared with treatment with carboplatin/paclitaxel alone. Treatment with trastuzumab was associated with an additional cost of $144,335,895, but was associated with an increase of 2065 QALYs. The ICER was $69,903 per QALY, which was below our willingness-to-pay threshold. Sensitivity analysis demonstrated that this treatment strategy was cost-effective until the cost of 6 months of treatment surpassed $38,505 (baseline input: $27,562). CONCLUSION: We found that the addition of trastuzumab to carboplatin/paclitaxel was a cost-effective treatment strategy for patients with advanced/recurrent Her2/neu-positive UPSC.

DHES0815A, a novel antibody-drug conjugate targeting HER2/neu, is highly active against uterine serous carcinomas in vitro and in vivo.

OBJECTIVE: Uterine serous carcinoma (USC) is an aggressive histologic variant of endometrial cancer which portends a poor prognosis. DHES0815A is a novel antibody-drug-conjugate (ADC) which binds specifically to HER2 overexpressing tumors at a distinct epitope from that bound by trastuzumab and pertuzumab after which it delivers the toxic payload, PBD-MA, a DNA mono-alkylating agent. The objective of this study was to evaluate the preclinical activity of DHES0815A against primary USC cell lines and xenografts. METHODS: Twelve primary USC cell lines were assessed by immunohistochemistry (IHC) for HER2 protein expression and for C-erbB2 gene amplification using fluorescent in situ hybridization (FISH) analysis. Cell viability and bystander killing in USC cell lines after exposure to DHES0815A, the non-targeted ADC, and the unconjugated antibody (i.e. MHES0488A) were evaluated using flow cytometry-based-assays. In vivo activity of DHES0815A was tested against HER2/neu overexpressing USC xenografts. RESULTS: High HER2/neu protein expression was seen in 25% (3/12) of the primary USC cell lines. USC cell lines overexpressing HER2/neu were significantly more sensitive to DHES0815A when compared to the non-targeted control ADC (p < 0.001). DHES0815A did not induce significant bystander killing of HER2/neu negative tumors when admixed with HER2/neu positive tumors. DHES0815A caused growth-inhibition and increased survival in USC HER2/neu overexpressing xenografts when compared to controls (p < 0.01). CONCLUSIONS: DHES0815A is both highly selective and toxic to USC tumors overexpressing HER2/neu both in vitro and in vivo. HER2-directed ADCs, alone or in combination with other HER2/neu targeted agents may represent a novel treatment option for patients with tumors harboring HER2/neu overexpression refractory to trastuzumab and traditional chemotherapy.