External validation of a deep learning-based algorithm for detection of tall cells in papillary thyroid carcinoma: A multicenter study

The tall cell subtype (TC-PTC) is an aggressive subtype of papillary thyroid carcinoma (PTC). The TC-PTC is defined as a PTC comprising at least 30% epithelial cells that are three times as tall as they are wide. In practice, this definition is difficult to adhere to, resulting in high inter-observer variability. In this multicenter study, we validated a previously trained deep learning (DL)-based algorithm for detection of tall cells on 160 externally collected hematoxylin and eosin (HE)-stained PTC whole-slide images. In a test set of 360 manual annotations of regions of interest from 18 separate tissue sections in the external dataset, the DL-based algorithm detected TCs with a sensitivity of 90.6% and a specificity of 88.5%. The DL algorithm detected non-TC areas with a sensitivity of 81.6% and a specificity of 92.9%. In the validation datasets, 20% and 30% TC thresholds correlated with a significantly shorter relapse-free survival. In conclusion, the DL algorithm detected TCs in unseen, external scanned HE tissue slides with high sensitivity and specificity without any retraining.

Is it safe to operate selected low-risk endometrial cancer patients in secondary hospitals?

INTRODUCTION

The aim of this study was to assess the accuracy of a preoperative screening algorithm in identifying low-risk endometrial cancer (EC) patients to ensure optimal care.

METHODS

A total of 277 patients with primary EC confirmed through biopsy underwent magnetic resonance imaging (MRI). Patients with risk factors for advanced high-risk EC, such as non-endometrioid histology, high-grade differentiation status, deep myometrial invasion, or spread beyond the uterine corpus, were systematically excluded. The remaining preoperatively screened patients with stage IA low-grade endometrioid EC (EEC) (n = 93) underwent surgery in a tertiary hospital. The accuracy of the preoperative diagnosis was evaluated by comparing the findings with the postoperative histopathological results. Disease-free survival (DFS) and overall survival (OS) were analyzed using 8-year follow-up data.

RESULTS

Postoperative histopathological analysis revealed that all patients had grade 1-2 EEC localized to the corpus uteri. Only three patients had deep myometrial invasion (stage IB), but they remained disease-free after 6-9 years of follow-up. The median follow-up time for all patients was 8.7 years. The DFS was 7.6 years, and the OS was 8.6 years. Two patients with stage IA grade 1 EEC experienced relapse and, despite treatment, died of EC. No other EC-related deaths occurred.

CONCLUSIONS

The screening algorithm accurately identified low-risk EC patients without compromising survival. Therefore, the algorithm appears to be feasible for selecting patients for surgery in secondary hospitals.

Endometrial Carcinosarcomas are Almost Exclusively of p53abn Molecular Subtype After Exclusion of Mimics

INTRODUCTION

Our aim was to assess the molecular subtype(s) and perform a detailed morphologic review of tumors diagnosed as carcinosarcoma in a population-based cohort.

METHODS

Forty-one carcinosarcomas were identified from a cohort of 973 endometrial carcinomas diagnosed in 2016. We assessed immunostaining and sequencing data and undertook expert pathology reviews of these cases as well as all subsequently diagnosed (post-2016) carcinosarcomas of no specific molecular profile (NSMP) molecular subtype (n=3) from our institutions.

RESULTS

In the 2016 cohort, 37 of the 41 carcinosarcomas (91.2%) were p53abn, 2 (4.9%) were NSMP, and 1 each (2.4%) were POLEmut and mismatch repair deficiency molecular subtypes, respectively. Of the 4 non-p53abn tumors on review, both NSMP tumors were corded and hyalinized (CHEC) pattern endometrioid carcinoma, the mismatch repair deficiency tumor was a grade 1 endometrioid carcinoma with reactive stromal proliferation, and the POLEmut tumor was grade 3 endometrioid carcinoma with spindle cell growth, that is, none were confirmed to be carcinosarcoma on review. We found 11 additional cases among the 37 p53abn tumors that were not confirmed to be carcinosarcoma on the review (3 undifferentiated or dedifferentiated carcinomas, 5 carcinomas with CHEC features, 2 carcinomas showing prominent reactive spindle cell stroma, and 1 adenosarcoma). In the review of institutional cases reported as NSMP carcinosarcoma after 2016, 3 were identified (1 adenosarcoma and 2 mesonephric-like adenocarcinoma on review).

CONCLUSION

In this series, all confirmed endometrial carcinosarcomas were p53abn. The finding of any other molecular subtype in a carcinosarcoma warrants pathology review to exclude mimics.

Endometrial Pipelle Biopsy Computer-Aided Diagnosis: A Feasibility Study

Endometrial biopsies are important in the diagnostic workup of women who present with abnormal uterine bleeding or hereditary risk of endometrial cancer. In general, approximately 10% of all endometrial biopsies demonstrate endometrial (pre)malignancy that requires specific treatment. As the diagnostic evaluation of mostly benign cases results in a substantial workload for pathologists, artificial intelligence (AI)-assisted preselection of biopsies could optimize the workflow. This study aimed to assess the feasibility of AI-assisted diagnosis for endometrial biopsies (endometrial Pipelle biopsy computer-aided diagnosis), trained on daily-practice whole-slide images instead of highly selected images. Endometrial biopsies were classified into 6 clinically relevant categories defined as follows: nonrepresentative, normal, nonneoplastic, hyperplasia without atypia, hyperplasia with atypia, and malignant. The agreement among 15 pathologists, within these classifications, was evaluated in 91 endometrial biopsies. Next, an algorithm (trained on a total of 2819 endometrial biopsies) rated the same 91 cases, and we compared its performance using the pathologist's classification as the reference standard. The interrater reliability among pathologists was moderate with a mean Cohen's kappa of 0.51, whereas for a binary classification into benign vs (pre)malignant, the agreement was substantial with a mean Cohen's kappa of 0.66. The AI algorithm performed slightly worse for the 6 categories with a moderate Cohen's kappa of 0.43 but was comparable for the binary classification with a substantial Cohen's kappa of 0.65. AI-assisted diagnosis of endometrial biopsies was demonstrated to be feasible in discriminating between benign and (pre)malignant endometrial tissues, even when trained on unselected cases. Endometrial premalignancies remain challenging for both pathologists and AI algorithms. Future steps to improve reliability of the diagnosis are needed to achieve a more refined AI-assisted diagnostic solution for endometrial biopsies that covers both premalignant and malignant diagnoses.

Subclonal p53 immunostaining in the diagnosis of endometrial carcinoma molecular subtype

AIMS

The significance of subclonal expression of p53 (abrupt transition from wild-type to mutant-pattern staining) is not well understood, and the arbitrary diagnostic cut-off of 10% between NSMP and p53abn molecular subtypes of endometrial carcinoma (EC) has not been critically assessed. Our aim was to characterise subclonal p53 and discrepant p53 expression/TP53 sequencing results in EC and assess their clinical significance.

METHODS AND RESULTS

Subclonal p53 immuostaining on whole sections from 957 ECs was recorded. Agreement between TP53 mutational assessment and p53 immunostaining was evaluated. Subclonal p53 IHC staining was seen in 4.0% (38 of 957) of cases, with 23 of 957 (2.4%) showing mutant-pattern p53 staining in ≥10% of tumour cells. It was most commonly seen in POLEmut (nine of 65, 14%) and MMRd (13 of 274, 4.7%) EC ('multiple classifier' ECs), where subclonal p53 staining does not impact the molecular subtype diagnosis. Excluding POLEmut and MMRd EC, 11 of 957 (1.1%) showed ≥10% subclonal p53 from which four patients died of disease, while there were no deaths due to disease in the five patients with <10% mutant-pattern p53 staining. Agreement between p53 immunostaining and TP53 sequencing was 92.6%; most of the discrepant results were in the ultramutated POLEmut or hypermutated MMRd ECs. In NSMP and p53abn EC the agreement between IHC and sequencing was 95.8%.

CONCLUSIONS

Subclonal p53 staining ≥10% is present in only 1.1% of EC after excluding 'multiple classifier' ECs. The cut-off of ≥10% subclonal p53 staining identified patients at increased risk of dying from EC, supporting its use to diagnose p53abn molecular subtype.

Classification of Vulvar Squamous Cell Carcinoma and Precursor Lesions by p16 and p53 Immunohistochemistry: Considerations, Caveats, and an Algorithmic Approach

There is emerging evidence that vulvar squamous cell carcinoma (VSCC) can be prognostically subclassified into 3 groups based on human papillomavirus (HPV) and p53 status: HPV-associated (HPV+), HPV-independent/p53 wild-type (HPV-/p53wt), or HPV-independent/p53 abnormal (HPV-/p53abn). Our goal was to assess the feasibility of separating VSCC and its precursors into these 3 groups using p16 and p53 immunohistochemistry (IHC). A tissue microarray containing 225 VSCC, 43 usual vulvar intraepithelial neoplasia (uVIN/HSIL), 10 verruciform acanthotic vulvar intraepithelial neoplasia (vaVIN), and 34 differentiated VIN (dVIN), was stained for p16 and p53. Noncomplementary p16 and p53 patterns were resolved by repeating p53 IHC and HPV RNA in situ hybridization (ISH) on whole sections, and sequencing for TP53. Of 82 p16-positive VSCC, 73 (89%) had complementary p16 and p53 patterns and were classified into the HPV+ group, 4 (4.9%) had wild-type p53 staining, positive HPV ISH and were classified into the HPV+ group, whereas 5 (6.1%) had p53 abnormal IHC patterns (1 null, 4 overexpression), negativity for HPV ISH, and harbored TP53 mutations (1 splice site, 4 missense); they were classified as HPV-/p53abn. Of 143 p16-negative VSCC, 142 (99.3%) had complementary p53 and p16 patterns: 115 (80.4%) HPV-/p53abn and 27 (18.9%) HPV-/p53wt. One had a basal-sparing p53 pattern, positivity for HPV ISH and was negative for TP53 mutations-HPV+ category. The use of IHC also led to revised diagnoses-HSIL to dVIN (3/43), dVIN to vaVIN (8/34), and dVIN to HSIL (3/34). Overall, 215/225 VSCC (95.6%) could be easily classifiable into 3 groups with p16 and p53 IHC. We identified several caveats, with the major caveat being that "double-positive" p16/p53 should be classified as HPV-/p53abn. We propose an algorithm that will facilitate the application of p16 and p53 IHC to classify VSCC in pathology practice.

Preoperative CA125 Significantly Improves Risk Stratification in High-Grade Endometrial Cancer

Patients with high-grade endometrial carcinoma (EC) have an increased risk of tumor spread and lymph node metastasis (LNM). Preoperative imaging and CA125 can be used in work-up. As data on cancer antigen 125 (CA125) in high-grade EC are limited, we aimed to study primarily the predictive value of CA125, and secondarily the contributive value of computed tomography (CT) for advanced stage and LNM. Patients with high-grade EC (n = 333) and available preoperative CA125 were included retrospectively. The association of CA125 and CT findings with LNM was analyzed by logistic regression. Elevated CA125 ((>35 U/mL), (35.2% (68/193)) was significantly associated with stage III-IV disease (60.3% (41/68)) compared with normal CA125 (20.8% (26/125), [p < 0.001]), and with reduced disease-specific-(DSS) (p < 0.001) and overall survival (OS) (p < 0.001). The overall accuracy of predicting LNM by CT resulted in an area under the curve (AUC) of 0.623 (p < 0.001) independent of CA125. Stratification by CA125 resulted in an AUC of 0.484 (normal), and 0.660 (elevated). In multivariate analysis elevated CA125, non-endometrioid histology, pathological deep myometrial invasion ≥50%, and cervical involvement were significant predictors of LNM, whereas suspected LNM on CT was not. This shows that elevated CA125 is a relevant independent predictor of advanced stage and outcome specifically in high-grade EC.

A platform for efficient establishment and drug-response profiling of high-grade serous ovarian cancer organoids

The broad research use of organoids from high-grade serous ovarian cancer (HGSC) has been hampered by low culture success rates and limited availability of fresh tumor material. Here, we describe a method for generation and long-term expansion of HGSC organoids with efficacy markedly improved over previous reports (53% vs. 23%-38%). We established organoids from cryopreserved material, demonstrating the feasibility of using viably biobanked tissue for HGSC organoid derivation. Genomic, histologic, and single-cell transcriptomic analyses revealed that organoids recapitulated genetic and phenotypic features of original tumors. Organoid drug responses correlated with clinical treatment outcomes, although in a culture conditions-dependent manner and only in organoids maintained in human plasma-like medium (HPLM). Organoids from consenting patients are available to the research community through a public biobank and organoid genomic data are explorable through an interactive online tool. Taken together, this resource facilitates the application of HGSC organoids in basic and translational ovarian cancer research.

Abstract 5779: A platform utilizing high-grade serous ovarian cancer organoids for prospective patient stratification in functional precision medicine

High-grade serous ovarian cancer (HGSC) is the most prevalent and lethal ovarian cancer type. While HGSC usually responds well to primary treatment, most cases eventually relapse. Functional precision medicine - tailoring individualized treatments based on functional in vitro assays on patient-derived cells - has been recently employed in cancer clinical trials. Cancer organoids - three-dimensional, self-organizing, self-renewing cell cultures that recapitulate original tissue structure and function - have been applied as cellular models in these trials. However, in case of HGSC, organoid derivation has proven time consuming and inefficient, hindering their application in functional precision medicine due to a short time window, in which therapy for each patient needs to be selected.

To address this problem, we aimed to establish whether drug vulnerabilities at HGSC relapse could be predicted using organoids derived from the primary disease cells. We derived sequential organoid models from material sampled during primary treatment and at relapse. Then, for organoid pairs (primary-relapse), we performed large-scale drug response profiling of a library of 370 compounds (approved drugs or drugs in clinical development), in 384-well microplate format, alone or in combination with a standard HGSC chemotherapeutic agent carboplatin. First, we found that HGSC organoid responses to standard chemotherapeutics retrospectively correlated to observed clinical treatment outcomes. But further, for each patient we identified compounds with pronounced cytotoxicity both in the primary and in the relapsed model, amounting to 66% of all hits (7% were primary-specific and 27% relapse-specific). We then focused on identifying patient-specific hits rather than compounds displaying general toxicity in all patient models. Based on a potential clinical applicability, for three patients we selected compounds for validation in organoid outgrowth assay, with prolonged (&gt;1 month) drug-free period post-treatment. In two patients, AZD4573, a selective CDK9 inhibitor in clinical development for hematological malignancies, at nanomolar concentrations caused eradication of organoids when combined with carboplatin. Organoids from the third patient were vulnerable to nitazoxanide, an approved anti-helminthic agent and an inhibitor of mitochondrial oxidative phosphorylation. Importantly, the selected final hits were identified solely based on screening in organoid models from primary disease.

In summary, we here demonstrate that HGSC organoids derived from primary disease material predict a majority of patient-specific drug vulnerabilities of organoids derived from the relapsed HGSC lesions. This indicates that patient stratification in functional precision medicine for treatment of HGSC relapse could be prospectively performed at the primary disease stage.

Citation Format: Wojciech Senkowski, Laura Gall-Mas, Matias M. Falco, Yilin Li, Kari Lavikka, Mette C. Kriegbaum, Jaana Oikkonen, Daria Bulanova, Elin J. Pietras, Karolin Voßgröne, Yan-Jun Chen, Erdogan P. Erkan, Mia K. Høg, Ida M. Larsen, Tarja Lamminen, Katja Kaipio, Jutta Huvila, Anni Virtanen, Lars H. Engelholm, Pernille Christiansen, Eric Santoni Rugiu, Kaisa Huhtinen, Olli Carpén, Johanna Hynninen, Sampsa Hautaniemi, Anna Vähärautio, Krister Wennerberg. A platform utilizing high-grade serous ovarian cancer organoids for prospective patient stratification in functional precision medicine. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5779.

Molecular subtype stratified outcomes according to adjuvant therapy in endometrial cancer

OBJECTIVES

Recent data support the predictive implications of molecular subtype assignment in endometrial cancer (EC). Our objective was to retrospectively assess clinical outcomes according to adjuvant treatment received within EC molecular subtypes.

METHODS

Clinical outcomes (disease-specific and progression-free survival DSS/PFS) of EC patients from a single institution and population-based cohorts that had undergone molecular classification were assessed with respect to adjuvant therapy received and 2016 ESMO risk group.

RESULTS

2472 ECs were assessed; 184 (7.4%) POLEmut, 638 (25.8%) MMRd, 1223 (49.5%) NSMP and 427 (17.3%) p53abn. N = 774 (34.6%) of the cohort were ESMO 2016 high risk and 109 (4.8%) were advanced or metastatic. In patients with MMRd EC, assessed across and within stage, there was no observed benefit in DSS or PFS with the addition of chemotherapy +/- radiation compared to radiation alone in ESMO high risk (p = 0.694) or ESMO high, advanced, metastatic risk groups combined (p = 0.852). In patients with p53abn EC, adjuvant chemotherapy given with radiation was associated with significantly longer DSS compared to radiation alone in ESMO high risk (p = 0.007) and ESMO high, advanced and metastatic risk groups combined (p = 0.015), even when restricted to stage I disease (p < 0.001) and when compared in serous vs. non-serous histotypes (p = 0.009).

CONCLUSIONS

Adjuvant chemotherapy is associated with more favorable outcomes for patients with p53abn EC, including stage I disease and non-serous histotypes, but does not appear to add benefit within MMRd ECs for any stage of disease, consistent with PORTEC-3 molecular subanalysis. Prospective trials, assessing treatment efficacy within molecular subtype are needed, however these 'real-world' data should be considered when discussing adjuvant treatment with patients.

An immune score reflecting pro- and anti-tumoural balance of tumour microenvironment has major prognostic impact and predicts immunotherapy response in solid cancers

BACKGROUND

Cancer immunity is based on the interaction of a multitude of cells in the spatial context of the tumour tissue. Clinically relevant immune signatures are therefore anticipated to fundamentally improve the accuracy in predicting disease progression.

METHODS

Through a multiplex in situ analysis we evaluated 15 immune cell classes in 1481 tumour samples. Single-cell and bulk RNAseq data sets were used for functional analysis and validation of prognostic and predictive associations.

FINDINGS

By combining the prognostic information of anti-tumoural CD8⁺ lymphocytes and tumour supportive CD68⁺CD163⁺ macrophages in colorectal cancer we generated a signature of immune activation (SIA). The prognostic impact of SIA was independent of conventional parameters and comparable with the state-of-art immune score. The SIA was also associated with patient survival in oesophageal adenocarcinoma, bladder cancer, lung adenocarcinoma and melanoma, but not in endometrial, ovarian and squamous cell lung carcinoma. We identified CD68⁺CD163⁺ macrophages as the major producers of complement C1q, which could serve as a surrogate marker of this macrophage subset. Consequently, the RNA-based version of SIA (ratio of CD8A to C1QA) was predictive for survival in independent RNAseq data sets from these six cancer types. Finally, the CD8A/C1QA mRNA ratio was also predictive for the response to checkpoint inhibitor therapy.

INTERPRETATION

Our findings extend current concepts to procure prognostic information from the tumour immune microenvironment and provide an immune activation signature with high clinical potential in common human cancer types.

FUNDING

Swedish Cancer Society, Lions Cancer Foundation, Selanders Foundation, P.O. Zetterling Foundation, U-CAN supported by SRA CancerUU, Uppsala University and Region Uppsala.

Grade and Estrogen Receptor Expression Identify a Subset of No Specific Molecular Profile Endometrial Carcinomas at a Very Low Risk of Disease-Specific Death

Endometrial carcinoma (EC) can be divided into 4 prognostic molecular subtypes, and no specific molecular profile (NSMP) type is the most commonly occurring type (∼50%). Although described as having an intermediate to favorable prognosis, this subtype encompasses pathologically and molecularly diverse tumors. We aimed to identify factors associated with outcomes within the NSMP ECs that might be used to stratify prognosis and direct treatment. Clinicopathologic, immunohistochemical, and genetic features of a large series of NSMP EC were used to identify parameters that could identify the subset associated with a very favorable outcome (disease-specific death rate <5% at 5 years, termed low-risk NSMP). A total of 1110 NSMP ECs were profiled. In a univariate analysis, stage, grade, lymphovascular invasion, estrogen receptor (ER) and progesterone receptor (PR) expression, L1CAM overexpression, and mutations in PIK3CA were associated with disease-specific survival. Two critical features, grade and ER expression, identified a low-risk NSMP subset (grade 1-2, ER-positive [>1%], 84% of cases), which showed a 5-year disease-specific death rate of 1.6% across all stages and 1.4% within stage I. The remaining cases (high-risk NSMPs, grade 3, and/or ER-negative status) were responsible for most of the disease-specific deaths (disease-specific death rate at 5 years, 22.9%; hazard ratio compared with that of low-risk NSMPs: 16.3; 95% CI, 8.4-31.7). Within NSMP EC, the low-risk and high-risk categories were of prognostic significance independent of the stage on a multivariate analysis. Low-grade and ER-positive NSMP ECs are a homogeneous low-risk group associated with an exceptionally favorable prognosis in which de-escalation and/or endocrine therapy strategies can be applied. Grade 3 and/or ER-negative status identifies a high-risk NSMP subset, including rare high-grade histotypes (eg, clear cell, dedifferentiated, and mesonephric-like), responsible for most NSMP-related deaths. Subclassification of NSMPs allows for the category of low-risk EC molecular subtypes to be dramatically expanded because it now includes both POLEmut and the much more common low-risk NSMP EC.

Histological findings in resected leiomyomas following MR-HIFU treatment, single-institution data from seven patients with unfavorable focal therapy

PURPOSE

Magnetic resonance - high-intensity focused ultrasound (MR-HIFU) is a noninvasive treatment option for symptomatic uterine leiomyomas. Currently, pretreatment MRI is used to assess tissue characteristics and predict the most likely therapeutic response for individual patients. However, these predictions still entail significant uncertainties. The impact of tissue properties on therapeutic outcomes remains poorly understood and detailed knowledge of the histological effects of ultrasound ablation is lacking. Investigating these aspects could aid in optimizing patient selection, enhancing treatment effects and improving treatment outcomes.

METHODS AND MATERIALS

We present seven patients who underwent MR-HIFU treatment for leiomyoma followed by second-line surgical treatment. Tissue samples obtained during the surgery were stained with hematoxylin and eosin, Masson's trichrome and Herovici to evaluate general morphology, fibrosis and collagen deposition of leiomyomas. Immunohistochemical CD31, Ki-67 and MMP-2 stainings were performed to study vascularization, proliferation and matrix metalloproteinase-2 protein expression in leiomyomas, respectively.

RESULTS

The clinical characteristics and radiological findings of the leiomyomas prior to treatment as well as qualitative histological findings after the treatment are presented and discussed in the context of current literature. A tentative model for volume reduction is presented.

CONCLUSION

These findings provide insights into potential factors contributing to suboptimal therapeutic outcomes and the variability in histological changes following treatment.

Relevance of Molecular Profiling in Patients With Low-Grade Endometrial Cancer

IMPORTANCE

Patients with low-grade (ie, grade 1-2) endometrial cancer (EC) are characterized by their favorable prognosis compared with patients with high-grade (ie, grade 3) EC. With the implementation of molecular profiling, the prognostic relevance of tumor grading might lose attention. As most patients present with low-grade EC and have an excellent outcome, the value of molecular profiling for these patients is unclear.

OBJECTIVE

To determine the association of molecular profiling with outcomes among patients with low-grade EC.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included a multicenter international European cohort of patients diagnosed with EC between 1994 and 2018, with a median follow-up of 5.9 years. Molecular subgroups were determined by next-generation sequencing using single-molecule molecular inversion probes and by immunohistochemistry. Subsequently, tumors were classified as polymerase epsilon (POLE)-altered, microsatellite instable (MSI), tumor protein p53 (TP53)-altered, or no specific molecular profile (NSMP). Patients diagnosed with any histological subtypes and FIGO (International Federation of Gynecology and Obstetrics) stages of EC were included, but patients with early-stage EC (FIGO I-II) were only included if they had known lymph node status. Data were analyzed February 20 to June 16, 2022.

EXPOSURES

Molecular testing of the 4 molecular subgroups.

MAIN OUTCOMES AND MEASURES

The main outcome was disease-specific survival (DSS) within the molecular subgroups.

RESULTS

A total of 393 patients with EC were included, with a median (range) age of 64.0 (31.0-86.0) years and median (range) body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 29.1 (18.0-58.3). Most patients presented with early-stage (290 patients [73.8%]) and low-grade (209 patients [53.2%]) disease. Of all patients, 33 (8.4%) had POLE-altered EC, 78 (19.8%) had MSI EC, 72 (18.3%) had TP53-altered EC, and 210 (53.4%) had NSMP EC. Across all molecular subgroups, patients with low-grade EC had superior 5-year DSS compared with those with high-grade EC, varying between 90% to 100% vs 41% to 90% (P < .001). Multivariable analysis in the entire cohort including age, tumor grade, FIGO stage, lymphovascular space invasion, and the molecular subgroups as covariates found that only high-grade (hazard ratio [HR], 4.29; 95% CI, 2.15-8.53; P < .001), TP53-altered (HR, 1.76; 95% CI, 1.04-2.95; P = .03), and FIGO stage III or IV (HR, 4.26; 95% CI, 2.50-7.26; P < .001) disease were independently associated with reduced DSS.

CONCLUSIONS AND RELEVANCE

This cohort study found that patients with low-grade EC had an excellent prognosis independent of molecular subgroup. These findings do not support routine molecular profiling in patients with low-grade EC, and they demonstrate the importance of primary diagnostic tumor grading and selective profiling in low-grade EC to increase cost-effectiveness.

The proteome of clear cell ovarian carcinoma

Clear cell ovarian carcinoma (CCOC) is the second most common subtype of epithelial ovarian carcinoma. Late-stage CCOC is not responsive to gold-standard chemotherapy and results in suboptimal outcomes for patients. In-depth molecular insight is urgently needed to stratify the disease and drive therapeutic development. We conducted global proteomics for 192 cases of CCOC and compared these with other epithelial ovarian carcinoma subtypes. Our results showed distinct proteomic differences in CCOC compared with other epithelial ovarian cancer subtypes including alterations in lipid and purine metabolism pathways. Furthermore, we report potential clinically significant proteomic subgroups within CCOC, suggesting the biologic plausibility of stratified treatment for this cancer. Taken together, our results provide a comprehensive understanding of the CCOC proteomic landscape to facilitate future understanding and research of this disease. © 2022 The Pathological Society of Great Britain and Ireland.

The amount of preoperative endometrial tissue surface in relation to final endometrial cancer classification

OBJECTIVE

To evaluate whether the amount of preoperative endometrial tissue surface is related to the degree of concordance with final low- and high-grade endometrial cancer (EC). In addition, to determine whether discordance is influenced by sampling method and impacts outcome.

METHODS

A retrospective cohort study within the European Network for Individualized Treatment of Endometrial Cancer (ENITEC). Surface of preoperative endometrial tissue samples was digitally calculated using ImageJ. Tumor samples were classified into low-grade (grade 1-2 endometrioid EC (EEC)) and high-grade (grade 3 EEC + non-endometroid EC).

RESULTS

The study cohort included 573 tumor samples. Overall concordance between pre- and postoperative diagnosis was 60.0%, and 88.8% when classified into low- and high-grade EC. Upgrading (preoperative low-grade, postoperative high-grade EC) was found in 7.8% and downgrading (preoperative high-grade, postoperative low-grade EC) in 26.7%. The median endometrial tissue surface was significantly lower in concordant diagnoses when compared to discordant diagnoses, respectively 18.7 mm2 and 23.5 mm2 (P = 0.022). Sampling method did not influence the concordance in tumor classification. Patients with preoperative high-grade and postoperative low-grade showed significant lower DSS compared to patients with concordant low-grade EC (P = 0.039).

CONCLUSION

The amount of preoperative endometrial tissue surface was inversely related to the degree of concordance with final tumor low- and high-grade. Obtaining higher amount of preoperative endometrial tissue surface does not increase the concordance between pre- and postoperative low- and high-grade diagnosis in EC. Awareness of clinically relevant down- and upgrading is crucial to reduce subsequent over- or undertreatment with impact on outcome.

Significance of p53 and presence of differentiated vulvar intra-epithelial neoplasia (dVIN) at resection margin in early stage human papillomavirus-independent vulvar squamous cell carcinoma

OBJECTIVE

Vulvar squamous cell carcinoma and in situ lesions can be stratified by human papillomavirus (HPV) and TP53 status into prognostic risk groups using p16 and p53 immunohistochemistry. We assessed the significance of vulvar squamous cell carcinoma resection margin positivity for either differentiated vulvar intra-epithelial neoplasia (dVIN) or abnormal p53 immunohistochemistry, and other pathologic variables, in a cohort of patients with HPV-independent (HPV-I) p53 abnormal (p53abn) vulvar squamous cell carcinomas.

METHODS

Patients with stage I-II HPV-I p53abn vulvar squamous cell carcinoma with negative invasive margins who did not receive adjuvant radiation from a single institution were included. Tumors underwent margin reassessment using p53 immunohistochemistry. Cases were segregated into (1) morphologic dVIN at margin; or (2) abnormal p53 immunohistochemistry staining at margin without morphologic dVIN (p53abn immunohistochemistry); or (3) margins negative by morphology and p53 immunohistochemistry. Clinicopathologic/outcome data were collected.

RESULTS

A total of 51 patients were evaluated: (1) 12 with dVIN on margin; (2) 12 with p53abn immunohistochemistry on margin without morphologic dVIN; and (3) 27 with margins negative for morphologic dVIN and p53abn immunohistochemistry. The recurrence rate for patients with dVIN or p53abn immunohistochemistry on the margin was equally high at 75% each, compared with 33% with margins negative for morphologic dVIN and p53abn immunohistochemistry (p=0.009). On multivariate analysis, positive in situ margins maintained an association with disease recurrence (p=0.03) whereas invasive margin distance (radial and deep), lymphovascular invasion, and tumor size did not.

CONCLUSIONS

Patients with stage I-II HPV-I vulvar squamous cell carcinoma with margins positive for either dVIN or p53abn immunohistochemistry without morphologic dVIN showed increased disease recurrence, regardless of invasive margin distance. These findings show that p53 immunohistochemistry is a useful adjunct for evaluating margin status in HPV-I vulvar squamous cell carcinoma and may support repeat excision for positive in situ margins (dVIN or p53abn immunohistochemistry).

Molecular subclassification of vulvar squamous cell carcinoma: reproducibility and prognostic significance of a novel surgical technique

OBJECTIVES

Vulvar squamous cell carcinoma is subclassified into three prognostically relevant groups: (i) human papillomavirus (HPV) associated, (ii) HPV independent p53 abnormal (mutant pattern), and (iii) HPV independent p53 wild type. Immunohistochemistry for p16 and p53 serve as surrogates for HPV viral integration and TP53 mutational status. We assessed the reproducibility of the subclassification based on p16 and p53 immunohistochemistry and evaluated the prognostic significance of vulvar squamous cell carcinoma molecular subgroups in a patient cohort treated by vulvar field resection surgery.

METHODS

In this retrospective cohort study, 68 cases treated by vulvar field resection were identified from the Leipzig School of Radical Pelvic Surgery. Immunohistochemistry for p16 and p53 was performed at three different institutions and evaluated independently by seven pathologists and two trainees. Tumors were classified into one of four groups: HPV associated, HPV independent p53 wild type, HPV independent p53 abnormal, and indeterminate. Selected cases were further interrogated by (HPV RNA in situ hybridization, TP53 sequencing).

RESULTS

Final subclassification yielded 22 (32.4%) HPV associated, 41 (60.3%) HPV independent p53 abnormal, and 5 (7.3%) HPV independent p53 wild type tumors. Interobserver agreement (overall Fleiss' kappa statistic) for the four category classification was 0.74. No statistically significant differences in clinical outcomes between HPV associated and HPV independent vulvar squamous cell carcinoma were observed.

CONCLUSION

Interobserver reproducibility of vulvar squamous cell carcinoma subclassification based on p16 and p53 immunohistochemistry may support routine use in clinical practice. Vulvar field resection surgery showed no significant difference in clinical outcomes when stratified based on HPV status.

Variation in practice in endometrial cancer and potential for improved care and equity through molecular classification

OBJECTIVES

We measured the variation in practice across all aspects of endometrial cancer (EC) management and assessed the potential impact of implementation of molecular classification.

METHODS

Centers from across Canada provided representative tumor samples and clinical data, including preoperative workup, operative management, hereditary cancer program (HCP) referrals, adjuvant therapy, surveillance and outcomes, for all EC patients diagnosed in 2016. Tumors were classified into the four ProMisE molecular subtypes.

RESULTS

A total of 1336 fully evaluable EC patients were identified from 10 tertiary cancer centers (TC; n = 1022) and 19 community centers (CC; n = 314). Variation of surgical practice across TCs was profound (14-100%) for lymphadenectomy (LND) (mean 57% Gr1/2, 82% Gr3) and omental sampling (20% Gr1/2, 79% Gr3). Preoperative CT scans were inconsistently obtained (mean 32% Gr1/2, 51% Gr3) and use of adjuvant chemo or chemoRT in high risk EC ranged from 0-55% and 64-100%, respectively. Molecular subtyping was performed retrospectively and identified 6% POLEmut, 28% MMRd, 48% NSMP and 18% p53abn ECs, and was significantly associated with survival. Within patients retrospectively diagnosed with MMRd EC only 22% had been referred to HCP. Of patients with p53abn EC, LND and omental sampling was not performed in 21% and 23% respectively, and 41% received no chemotherapy. Comparison of management in 2016 with current 2020 ESGO/ESTRO/ESP guidelines identified at least 26 and 95 patients that would have been directed to less or more adjuvant therapy, respectively (10% of cohort).

CONCLUSION

Molecular classification has the potential to mitigate the profound variation in practice demonstrated in current EC care, enabling reproducible risk assessment, guiding treatment and reducing health care disparities.

Combined expression of HOXA11 and CD10 identifies endometriosis versus normal tissue and tumors

The gold standard for diagnosing endometriosis is by laparoscopic visual demonstration of ectopic endometrial lesions outside the uterus, preferably verified by biopsy and microscopical examination. Molecular markers to facilitate the microscopical diagnosis of endometriosis and for distinguishing endometriosis from other benign and malignant lesions are lacking. Our aim was to test and validate an immunohistochemical antibody panel for improved diagnostic accuracy of endometriosis. Both CD10 and HOXA11 have been implicated in regulation of endometrial homeostasis. Here we have analyzed the expression pattern of these two proteins using immunohistochemistry on human tissues in a tissue microarray format. CD10 and HOXA11 expression in endometriosis lesions were compared to expression patterns in a range of normal tissues and in primary- and metastatic lesions of endometrial-, cervical- and ovarian cancer. HOXA11 and CD10 were expressed in 98% and 91% of endometriosis lesions and the combined double-positive expression profile of both HOXA11 and CD10 was highly sensitive for ectopic endometrial tissue (90%). The specificity and sensitivity for this double-positive signature in endometriosis was significantly different from all investigated tissues, cancers and metastases except normal, eutopic endometrial- and cervical mucosa. The combination of HOXA11 and CD10 expression profiles provides a useful tool to identify ectopic endometrial tissue and for distinguishing endometriosis from various types of gynecological malignancies and metastases.

STING pathway expression in low-grade serous carcinoma of the ovary: an unexpected therapeutic opportunity?

Ovarian carcinoma histotypes are distinct diseases with variable clinical outcomes and response to treatment. There is a need for new subtype-specific treatment modalities, especially for women with widespread and chemo-resistant disease. Stimulator of interferon genes (STING) is a part of the cGAS-STING pathway that mediates innate immune defence against infectious DNA-containing pathogens and also detects tumour-derived DNA and generates intrinsic antitumour immunity. The STING signalling pathway is suppressed by several mechanisms in a variety of malignant diseases and, in some cancers that may be a requirement for cellular transformation. The aim of this study was to use immunohistochemistry to evaluate STING protein expression across normal tissue, paratubal and ovarian cysts, and ovarian tumour histotypes including ovarian carcinomas. Herein, we show that the fallopian tube ciliated cells express STING protein, whereas the secretory cells are negative. STING expression differs among ovarian cancer histotypes; low-grade serous ovarian carcinomas and serous borderline tumours have uniform high STING expression, while high-grade serous and endometrioid carcinomas have heterogeneous expression, and clear cell and mucinous carcinomas show low expression. As low-grade serous carcinomas are known to be genomically stable and typically lack a prominent host immune response, the consistently high STING expression is unexpected. High STING expression may reflect pathway activation or histogenesis and the mechanisms may be different in different ovarian carcinoma histotypes. Further studies are needed to determine whether the STING signalling pathway is active and whether these tumours would be candidates for therapeutic interventions that trigger innate immunity activation.

Immunohistochemical biomarkers are prognostic relevant in addition to the ESMO-ESGO-ESTRO risk classification in endometrial cancer

OBJECTIVE

Pre-operative immunohistochemical (IHC) biomarkers are not incorporated in endometrial cancer (EC) risk classification. We aim to investigate the added prognostic relevance of IHC biomarkers to the ESMO-ESGO-ESTRO risk classification and lymph node (LN) status in EC.

METHODS

Retrospective multicenter study within the European Network for Individualized Treatment of Endometrial Cancer (ENITEC), analyzing pre-operative IHC expression of p53, L1 cell-adhesion molecule (L1CAM), estrogen receptor (ER) and progesterone receptor (PR), and relate to ESMO-ESGO-ESTRO risk groups, LN status and outcome.

RESULTS

A total of 763 EC patients were included with a median follow-up of 5.5-years. Abnormal IHC expression was present for p53 in 112 (14.7%), L1CAM in 79 (10.4%), ER- in 76 (10.0%), and PR- in 138 (18.1%) patients. Abnormal expression of p53/L1CAM/ER/PR was significantly related with higher risk classification groups, and combined associated with the worst outcome within the 'high and advanced/metastatic' risk group. In multivariate analysis p53-abn, ER/PR- and ESMO-ESGO-ESTRO 'high and advanced/metastatic' were independently associated with reduced disease-specific survival (DSS). Patients with abnormal IHC expression and lymph node metastasis (LNM) had the worst outcome. Patients with LNM and normal IHC expression had comparable outcome with patients without LNM and abnormal IHC expression.

CONCLUSION

The use of pre-operative IHC biomarkers has important prognostic relevance in addition to the ESMO-ESGO-ESTRO risk classification and in addition to LN status. For daily clinical practice, p53/L1CAM/ER/PR expression could serve as indicator for surgical staging and refine selective adjuvant treatment by incorporation into the ESMO-ESGO-ESTRO risk classification.

Molecular subtype diagnosis of endometrial carcinoma: comparison of the next-generation sequencing panel and Proactive Molecular Risk Classifier for Endometrial Cancer classifier

The Cancer Genome Atlas-based molecular classification of endometrial carcinoma (EC) has the potential to better identify those patients whose disease is likely to behave differently than predicted when using traditional risk stratification; however, the optimal approach to molecular subtype assignment in routine practice remains undetermined. The aim of this study was to compare the results of two different widely available approaches to diagnosis the EC molecular subtype. EC specimens from 60 patients were molecularly subclassified using two different methods, by using the FoundationOne CDx next-generation sequencing (NGS) panel and using the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) classifier and performing immunostaining for mismatch repair proteins and p53. POLE mutation status was derived from FoundationOne results in both settings. Molecular classification based on ProMisE was successful for all 60 tumors. Microsatellite instability status could be determined based on the NGS panel results in 53 of 60 tumors, so ProMisE and NGS molecular subtype assignment could be directly compared for these 53 tumors. Molecular subtype diagnosis based on NGS and ProMisE was in agreement for 52 of 53 tumors. One tumor was microsatellite stable but showed loss of MLH1 and PMS2 expression. Molecular subtype diagnosis of EC based on the NGS panel of formalin-fixed paraffin-embedded ECs and based primarily on immunostaining (ProMisE) yields identical results in 98.1% (52/53, kappa = 0.97) of cases. Although results obtained using these two approaches are comparable, each has advantages and disadvantages that will influence the choice of the method to be used in clinical practice.

Online Training and Self-assessment in the Histopathologic Classification of Endocervical Adenocarcinoma and Diagnosis of Pattern of Invasion: Evaluation of Participant Performance

Histopathologic classification of endocervical adenocarcinomas (EAC) has recently changed, with the new system based on human papillomavirus (HPV)-related morphologic features being incorporated into the 5th edition of the WHO Blue Book (Classification of Tumours of the Female Genital Tract). There has also been the introduction of a pattern-based classification system to assess invasion in HPV-associated (HPVA) endocervical adenocarcinomas that stratifies tumors into 3 groups with different prognoses. To facilitate the introduction of these changes into routine clinical practice, websites with training sets and test sets of scanned whole slide images were designed to improve diagnostic performance in histotype classification of endocervical adenocarcinoma based on the International Endocervical Adenocarcinoma Criteria and Classification (IECC) and assessment of Silva pattern of invasion in HPVA endocervical adenocarcinomas. We report on the diagnostic results of those who have participated thus far in these educational websites. Our goal was to identify areas where diagnostic performance was suboptimal and future educational efforts could be directed. There was very good ability to distinguish HPVA from HPV-independent adenocarcinomas within the WHO/IECC classification, with some challenges in the diagnosis of HPV-independent subtypes, especially mesonephric carcinoma. Diagnosis of HPVA subtypes was not consistent. For the Silva classification, the main challenge was related to distinction between pattern A and pattern B, with a tendency for participants to overdiagnose pattern B invasion. These observations can serve as the basis for more targeted efforts to improve diagnostic performance.

p53abn Endometrial Cancer: understanding the most aggressive endometrial cancers in the era of molecular classification

Over the past decade, our understanding of endometrial cancer has changed dramatically from the two-tiered clinicopathologic classification system of type I and type II endometrial cancer through to the four distinct molecular subtypes identified by The Cancer Genome Atlas (TCGA) in 2013. In both systems there is a small subset of endometrial cancers (serous histotype/high numbers of somatic copy number abnormalities) that account for a disproportionately high percentage of endometrial cancer related deaths. This subset can be identified in routine clinical practice by first identifying the approximately one-third of endometrial cancers that are either ultramutated/POLEmut tumors, with pathogenic mutations in the exonuclease domain of POLE, or hypermutated/MMRd tumors, with loss of DNA mismatch repair. Immunostaining for p53 stratifies the remaining endometrial cancers into those with wild-type staining pattern and those with mutant pattern staining (p53abn endometrial cancer). This latter group of p53abn endometrial cancer is the subject of this review. Most p53abn endometrial cancers are serous type and high grade, but it also includes other histotypes and lower grade tumors, and has consistently been associated with the poorest clinical outcomes. Although it only accounts for 15% of all endometrial cancer cases, it is responsible for 50-70% of endometrial cancer mortality. A better understanding of the molecular alterations in the p53abn subgroup, beyond the ubiquitous and definitional TP53 mutations, is required so we can identify better treatments for these most aggressive endometrial cancers. Recent evidence has shown improved survival outcomes with the addition of chemotherapy compared with radiation alone in p53abn endometrial cancers. Opportunities for targeted therapy for p53abn endometrial cancers also exist with a proportion of p53abn endometrial cancers known to have homologous recombination deficiency (HRD) or human epidermal growth factor 2 (HER2) overexpression/amplification. This review will provide an overview of our current understanding of p53abn endometrial cancer.

Endometrial carcinoma: molecular subtypes, precursors and the role of pathology in early diagnosis

Endometrial carcinoma (EC) is classified into a wide range of morphological variants; this list has expanded over the past decade with the inclusion of mesonephric-like and dedifferentiated carcinoma as EC variants in the fifth edition of the WHO Classification of Female Genital Tumours, and recognition that carcinosarcoma is a biphasic carcinoma rather than a sarcoma. Each EC variant has distinct molecular abnormalities, including TCGA-based molecular subtypes, allowing further subclassification and adding complexity. In contrast to this rapid progress in understanding EC, there are only two recognized EC precursor lesions: endometrial atypical hyperplasia/endometrioid intraepithelial neoplasia (EAH/EIN) and serous intraepithelial carcinoma, a situation that has not changed for many years. Diagnosis of EC precursors is a cornerstone of surgical pathology practice, with early diagnosis contributing to the relatively favorable prognosis of EC. In this review we relate the precursor lesions to each of the EC morphological variants and molecular subtypes, discuss how successful early diagnosis is for each variant/molecular subtype and how it might be improved, and identify knowledge gaps where there is insufficient understanding of EC histogenesis. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Abstract PR002: Global proteomic profiling of endometrial carcinomas identify prognostic markers

While endometrial cancer (EC) has an overall good prognosis, some patients do poorly and there is room for refinement within current classification systems. Using the TCGA prognostic grouping of EC, our group developed the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE), which reliably and reproducibly stratifies ECs into four prognostic groups: POLEmut, p53wt/NSMP, MMRd (mismatch repair deficient), and p53abn, with the best prognosis for POLEmut to worst prognosis for p53abn. In the current study, global proteomic analysis was performed using the clinical SP3-CTP workflow on archival tissues from 151 patients including 40 MMRd, 34 POLEmut, 34 p53abn and 43 p53wt/NSMP, with clinical follow up data. Included in the cohort were 11 replicate samples (different parts of the same tumor) to examine spatial heterogeneity in the proteomic profiles. Replicate samples were highly correlated to each other, with the exception of three POLEmut cases with very poor correlation in the proteome in different parts of the tumor. As POLEmut tumors have an exceedingly high mutation burden, it is not surprising that this translates to heterogeneity at the proteomic level. Disease specific survival was examined to determine prognostic significance within the whole cohort and within individual molecular subgroups. High TOMM34, PLTP or TSFM expression was correlated to poor disease specific survival in the whole cohort and independently prognostic when molecular subtype, grade and histotype are considered. High MGST, NCL or XPNPEP3 were associated with poor outcomes within the p53wt/NSMP group. POLD2 and ENAH were prognostic within the MMRd group. Within the p53abn group, ACADVL and BABAM1 were found to be prognostic, and GRB7 was found to be enriched in the p53abn group compared to other molecular subtypes. As the group with the worst prognosis, p53abn group could benefit from novel therapeutic avenues. ACADVL, BABAM1 and GRB7 all lie within pathways that are potentially targetable. Our proteomic analysis has identified prognostic markers that may be useful in further refining current molecular classification to help guide treatment decisions. Furthermore, new therapeutic interventions could be developed to target proteins and pathways identified by this proteomics screen.

Citation Format: Dawn R. Cochrane, Gian Negri, Jutta Huvila, David A. Farnell, Emily Thompson, Winnie Yang, Genny Trigo-Gonzales, Amy Lum, Sandra Spencer, Ryan Riley, Samuel Leung, Christine Chow, Jamie Lim, Martin Koebel, Stefan Kommoss, Friedrich Kommoss, Lien Hoang, David G. Huntsman, Gregg Morin, Jessica N. McAlpine. Global proteomic profiling of endometrial carcinomas identify prognostic markers [abstract]. In: Proceedings of the AACR Virtual Special Conference: Endometrial Cancer: New Biology Driving Research and Treatment; 2020 Nov 9-10. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(3_Suppl):Abstract nr PR002.

The cutoff for estrogen and progesterone receptor expression in endometrial cancer revisited: a European Network for Individualized Treatment of Endometrial Cancer collaboration study

There is no consensus on the cutoff for positivity of estrogen receptor (ER) and progesterone receptor (PR) in endometrial cancer (EC). Therefore, we determined the cutoff value for ER and PR expression with the strongest prognostic impact on the outcome. Immunohistochemical expression of ER and PR was scored as a percentage of positive EC cell nuclei. Cutoff values were related to disease-specific survival (DSS) and disease-free survival (DFS) using sensitivity, specificity, and multivariable regression analysis. The results were validated in an independent cohort. The study cohort (n = 527) included 82% of grade 1-2 and 18% of grade 3 EC. Specificity for DSS and DFS was highest for the cutoff values of 1-30%. Sensitivity was highest for the cutoff values of 80-90%. ER and PR expression were independent markers for DSS at cutoff values of 10% and 80%. Consequently, three subgroups with distinct clinical outcomes were identified: 0-10% of ER/PR expression with, unfavorable outcome (5-year DSS = 75.9-83.3%); 20-80% of ER/PR expression with, intermediate outcome (5-year DSS = 93.0-93.9%); and 90-100% of ER/PR expression with, favorable outcome (5-year DSS = 97.8-100%). The association between ER/PR subgroups and outcomes was confirmed in the validation cohort (n = 265). We propose classification of ER and PR expression based on a high-risk (0-10%), intermediate-risk (20-80%), and low-risk (90-100%) group.

p53 Immunohistochemical patterns in HPV-related neoplasms of the female lower genital tract can be mistaken for TP53 null or missense mutational patterns

We have recently encountered p53 immunohistochemical (IHC) patterns in human papillomavirus (HPV)-associated carcinomas of the gynecologic tract, which were confused with absent (null) or overexpression TP53 mutational staining. We therefore evaluated p53 and p16 IHC in 25 squamous cell carcinomas (SCC) (16 vulva, 4 Bartholin's gland, and 5 cervix), 20 endocervical adenocarcinomas (EDAC), 14 high-grade squamous intraepithelial lesions (HSIL), 2 adenocarcinoma in situ (AIS), all of which exhibited morphologic features of HPV. Only cases showing diffuse/strong block-like p16 staining were included for further study. All EDACs underwent TP53 sequencing and HPV in situ hybridization (ISH) was performed in selected cases. p53 IHC staining fell into two main patterns. The most common was designated as "markedly reduced (null-like)" (absence or significantly attenuated staining in >70% of cells), which could be confused with true null mutational pattern. This was present in 14/25 (56%) SCCs, 7/14 (50%) HSILs, and 18/20 (90%) EDACs. The second notable pattern was "mid-epithelial (basal sparing)" (distinct absence of staining in basal cells juxtaposed with strong staining in parabasal cells), seen in 10/25 (40%) SCC, 7/14 (50%) HSIL, and none of the EDACs. There was scattered weak to moderate p53 staining (conventional wild type) in 1/25 (4%) SCC and 2/20 (10%) EDAC. No cases showed strong/diffuse overexpression. One EDAC had a TP53 missense mutation and exhibited "markedly reduced (null-like)" staining. HPV ISH revealed an inverse relationship with p53, cells positive for HPV mRNA were negative for p53. Knowledge of these patterns can help pathologists avoid misinterpreting p53 status in the setting of HPVA cancers.

Abstract 4879: Poor outcome in hypoxic endometrial carcinoma is related to vascular density

Optimal identification of endometrial carcinoma (EC) patients at high risk of recurrence is currently lacking. Hypoxia is an important feature of aggressive EC leading to activation of hypoxic and angiogenetic target genes. The present study investigates the prognostic role of hypoxia and angiogenesis in EC. Data and tissues were used from 11 collaborating European Network for Individualized Treatment of Endometrial Cancer (ENITEC) centers. Tumor slides were stained for CAIX as a hypoxic marker and CD-34 for assessment of microvessel density (MVD) as a marker for angiogenesis. Complete slides were digitalized and analyzed using ImageJ software after exclusion of areas without tumor. A cutoff of 1% for the fraction of CAIX positive tumor cells was used. The MVD was assessed according to the Weidner method with the median as cutoff. Correlations with disease-specific survival (DSS), disease-free survival (DFS) and distant disease-free survival (DDFS) were calculated using Cox regression analysis. Sixty-three (16.4%) of 385 ECs showed positive CAIX-expression with high vascular density. Multivariable analysis showed that ECs with combined positive CAIX-expression and high vascular density had a reduced DSS (hazard ratio [HR] 3.71, p = 0.002) and DDFS (HR 2.68, p = 0.009) and a trend for reduced DFS (HR 1.87, p = 0.054). Multivariable analyses with CAIX-expression and vascular density as separate markers, showed that both were independent prognostic markers as well. This study found an impaired DSS and DDFS in ECs with positive CAIX-expression and high vascular density. Differential adjuvant treatment might be indicated for these ECs.

Citation Format: Casper Reijnen, Willem Jan van Weelden, Martijn SJP Arts, Johan P. Peters, Paul F. Rijken, Koen van de Vijver, Maria Santacana, Peter Bronsert, Johan Bulten, Marc Hirschfeld, Eva Colas, Antonio Gil-Moreno, Amando Reques, Gemma Mancebo, Fransesc Alameda, Camilla Krakstad, Jone Trovik, Ingfrid S. Haldorsen, Jutta Huvila, Stefanie Schrouwen, Martin Koskas, Francine Walker, Vit Weinberger, Lubos Minar, Eva Jandakova, Marc PLM Snijders, Saskia van den Berg-van Erp, Heidi VN Küsters-Vandevelde, Xavier Matias-Guiu, Frederic Amant, ENITEC-consortium, Leon FAG Massuger, Johan Bussink, Johanna MA Pijnenborg. Poor outcome in hypoxic endometrial carcinoma is related to vascular density [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4879.

Addition of IMP3 to L1CAM for discrimination between low- and high-grade endometrial carcinomas: a European Network for Individualised Treatment of Endometrial Cancer collaboration study

Discrimination between low- and high-grade endometrial carcinomas (ECs) is clinically relevant but can be challenging for pathologists, with moderate interobserver agreement. Insulin-like growth factor-II mRNA-binding protein 3 (IMP3) is an oncofoetal protein that is associated with nonendometrioid endometrial carcinomas but has been limited studied in endometrioid carcinomas. The aim of this study is to investigate the diagnostic and prognostic value of IMP3 in the discrimination between low- and high-grade ECs and its added value to L1CAM. IMP3 and L1CAM expression was assessed in tumors from 378 patients treated for EC at 1 of 9 participating European Network for Individualised Treatment of Endometrial Cancer centers. IMP3 was expressed in 24.6% of the tumors. In general, IMP3 was more homogeneously expressed than L1CAM. IMP3 expression was significantly associated with advanced stage, nonendometrioid histology, grade 3 tumors, deep myometrial invasion, lymphovascular space invasion, distant recurrences, overall mortality, and disease-related mortality. Simultaneous absence of IMP3 and L1CAM expression showed the highest accuracy for identifying low-grade carcinomas (area under the curve 0.766), whereas simultaneous expression of IMP3 and L1CAM was strongly associated with high-grade carcinomas (odds ratio 19.7; 95% confidence interval 9.2-42.2). Even within endometrioid carcinomas, this combination remained superior to IMP3 and L1CAM alone (odds ratio 8.6; 95% confidence interval 3.4-21.9). In conclusion, IMP3 has good diagnostic value and together with L1CAM represents the optimal combination of diagnostic markers for discrimination between low- and high-grade ECs compared to IMP3 and L1CAM alone. Because of the homogenous expression of IMP3, this marker might be valuable in preoperative biopsies when compared to the more patchy L1CAM expression.

L1CAM expression in endometrial carcinomas: an ENITEC collaboration study

Background:

Identification of aggressive endometrioid endometrial carcinomas (EECs) and non-endometrioid carcinomas (NEECs) is essential to improve outcome. L1 cell adhesion molecule (L1CAM) expression is a strong prognostic marker in stage I EECs, but less is known about L1CAM expression in advanced-stage EECs and NEECs. This study analyses L1CAM expression in a clinically representative cohort of endometrial carcinomas.

Methods:

The expression of L1CAM was immunohistochemically determined in 1199 endometrial carcinomas, treated at one of the European Network for Individualized Treatment of Endometrial Cancer (ENITEC) centres. Staining was considered positive when >10% of the tumour cells expressed L1CAM. The association between L1CAM expression and several clincopathological characteristics and disease outcome was calculated.

Results:

In all, L1CAM was expressed in 10% of the 935 stage I EECs, 18% of the 160 advanced stage EECs, and 75% of the 104 NEECs. The expression of L1CAM was associated with advanced stage, nodal involvement, high tumour grade, non-endometrioid histology, lymphovascular space invasion, and distant recurrences in all cases, and with reduced survival in the EECs, but not in the NEECs.

Conclusions:

The expression of L1CAM is a strong predictor of poor outcome in EECs, but not NEECs. It is strongly associated with non-endometrioid histology and distant spread, and could improve the postoperative selection of high-risk endometrial carcinomas. The value of L1CAM expression in the preoperative selection of high-risk endometrial carcinomas should be studied.

Loss of ASRGL1 expression is an independent biomarker for disease-specific survival in endometrioid endometrial carcinoma

OBJECTIVE

For endometrial carcinoma, prognostic stratification methods do not satisfactorily identify patients with adverse outcome. Currently, histology, tumor grade and stage are used to tailoring surgical treatment and to determine the need for adjuvant treatment. Low-risk patients are not considered to require adjuvant therapy or staging lymphadenectomy. For patients with intermediate or high risk, some guidelines recommend tailoring adjuvant treatment according to additional negative prognostic factors. Our objective was to evaluate the biomarker potential of the ASRGL1 protein in endometrial carcinoma.

METHODS

Using The Human Protein Atlas (www.proteinatlas.org), the l-asparaginase (ASRGL1) protein was identified as an endometrial carcinoma biomarker candidate. ASRGL1 expression was immunohistochemically evaluated with an extensively validated antibody on two independent endometrial carcinoma cohorts (n=229 and n=286) arranged as tissue microarrays. Staining results were correlated with clinical features.

RESULTS

Reduced expression of ASRGL1, defined as <75% positively stained tumor cells, was significantly associated with poor prognosis and reduced disease-specific survival in endometrioid endometrial adenocarcinoma (EEA). In multivariate analysis the hazard ratios for disease-specific survival were 3.55 (95% CI=1.10-11.43; p=0.003) and 3.23 (95% CI=1.53-6.81; p=0.002) in the two cohorts, respectively. Of the 48 cases with Grade 3 Stage I tumor all disease-related deaths were associated with low ASRGL1 expression.

CONCLUSIONS

Loss of ASRGL1 in EEA is a powerful biomarker for poor prognosis and retained ASRGL1 has a positive impact on survival. ASRGL1 immunohistochemistry has potential to become an additional tool for prognostication in cases where tailoring adjuvant treatment according to additional prognostic factors besides grade and stage is recommended.

Gene expression profiling of endometrial adenocarcinomas reveals increased apolipoprotein E expression in poorly differentiated tumors

INTRODUCTION

Tumor grade is one of the most important prognostic factors in endometrioid endometrial adenocarcinoma. Amplification of oncogenes, such as Her2/neu, or loss of function of tumor suppressor genes, such as p53, are known to be associated with poor prognosis, but additional factors influencing clinical behavior are likely to exist. To examine the biological differences between low-grade and high-grade endometrioid endometrial adenocarcinomas, we compared gene expression in these 2 types of tumors.

METHODS

Six well-differentiated adenocarcinomas and 7 poorly differentiated adenocarcinomas were studied with 2 different microarray platforms, Affymetrix and Illumina. The expression of the most differentially expressed gene on both platforms was further studied in 34 endometrial adenocarcinoma samples (10 well differentiated, 9 moderately differentiated, and 15 poorly differentiated) using real-time reverse transcription-polymerase chain reaction.

RESULTS

The most differentially expressed gene on both platforms was Apolipoprotein E (APOE). In the poorly differentiated adenocarcinomas, APOE was overexpressed 13.1-fold (P = 0.001) and 9.7-fold (P = 0.007) when compared with well- and moderately differentiated tumors, respectively. There was no difference in APOE expression between well- and moderately differentiated adenocarcinomas.

CONCLUSIONS

Increased expression of APOE might represent a late event in the progression of well-differentiated endometrioid endometrial adenocarcinoma to a poorly differentiated endometrioid endometrial adenocarcinoma. Although increased APOE expression has been previously reported in other malignancies, this is the first study to suggest that APOE might also have a role in endometrioid endometrial cancer.