Abstract 6499: Towards a combined immunohistochemistry-based subtyping of ovarian endometrioid carcinoma

Background: Ovarian endometrioid carcinoma (OEC) is an uncommon, understudied histotype that is distinguished from other histotypes by unique genomic features and high hormone receptor expression. There is growing interest in the biological relevance of subtyping using immunohistochemistry (IHC).

Methods: Women with primary invasive OEC diagnosed from 1989 to 2010 were retrospectively identified from the population-based Alberta Cancer Registry, Canada. Pathology slide review and IHC staining for Napsin A, TP53, and WT1 were used to reduce histologic misclassification, resulting in N=166 participants (low-stage N=138, high-stage N=28), excluding those who received neo-adjuvant chemotherapy. The following markers were stained and scored on tissue microarrays: TP53 (normal/abnormal), PMS2/MSH6 (mismatch repair proficient [MMRp]/deficient [MMRd]), PGR (loss/retained), and CTNNB1 (nuclear/cytoplasmic). Using a hierarchical decision tree by stage group (low/high), we categorized tumors as TP53 abnormal, MMRd, PGR loss, nuclear CTNNB1, and no specific immunohistochemical profile (NSIP). Distributions and five-year disease specific survival (DSS) was estimated for each group; hazard ratios (HRs) adjusted for age were estimated using Cox regression with NSIP as referent group.

Results: Among low-stage cases, five-year survival was as follows: 80% for TP53 abnormal (N=10, 7%), 87% for MMRd (N=15, 11%), 80% for PGR loss (N=10, 7%), 98% for nuclear CTNNB1 (N=63, 46%), and 95% for NSIP group (N=40, 29%). Overall, IHC group was associated with DSS among low stage cases (LRT p-value=0.006), and the group with nuclear CTNNB1 had a small but statistically significant DSS advantage (HR=0.089, 95% CI 0.011-0.742, p=0.025). TP53 and PGR loss suggested shorter DSS than the referent NSIP group, but not statistically significantly so (HR=1.26 and 3.08, respectively). Among high-stage cases, five-year DSS was as follows: 57% for TP53 abnormal (N=7, 25%), 75% for MMRd (N=8, 29%), 33% for nuclear CTNNB1 (N=3, 11%), and 17% for NSIP (N=10, 36%). There were no high-stage cases in the PGR-loss group. Nuclear CTNNB1 group had a shorter DSS among high-stage cases, but this was not statistically significantly so (HR=1.16, p=0.85).

Conclusion: Pending replication in additional datasets, results suggest that OEC cases in nuclear CTNNB1 or NSIP IHC groups may have a favorable prognosis in which de-escalation of therapy can be considered. In addition, abnormal TP53 and loss of PGR may identify a high-risk subset of low-stage OEC.

Citation Format: Brooke Jorgensen, Stacey Winham, Julie Cunningham, Sebastian Armasu, Chen Wang, Hunter Atkinson, Bryan McCauley, Linda Kelemen, Martin Koebel, Ellen Goode. Towards a combined immunohistochemistry-based subtyping of ovarian endometrioid carcinoma [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 6499.

Cancer cell genotype associated tumor immune microenvironment exhibits differential response to therapeutic STING pathway activation in high-grade serous ovarian cancer

Background

High-grade serous ovarian carcinoma (HGSC) is the most lethal gynecologic malignancy characterized by resistance to chemotherapy and high rates of recurrence. HGSC tumors display a high prevalence of tumor suppressor gene loss. Given the type 1 interferon regulatory function ofBRCA1andPTENgenes and their associated contrasting T-cell infiltrated and non-infiltrated tumor immune microenvironment (TIME) states, respectively, in this study we investigated the potential of stimulator of interferon genes (STING) pathway activation in improving overall survival via enhancing chemotherapy response, specifically in tumors with PTEN deficiency.

Methods

Expression of PTEN protein was evaluated in tissue microarrays generated using pretreatment tumors collected from a cohort of 110 patients with HGSC. Multiplex immunofluorescence staining was performed to determine spatial profiles and density of selected lymphoid and myeloid cells. In vivo studies using the syngeneic murine HGSC cell lines, ID8-Trp53–/–;Pten–/–and ID8-Trp53–/–;Brca1–/–, were conducted to characterize the TIME and response to carboplatin chemotherapy in combination with exogenous STING activation therapy.

Results

Patient tumors with absence of PTEN protein exhibited a significantly decreased disease specific survival and intraepithelial CD68+ macrophage infiltration as compared with intact PTEN expression. In vivo studies demonstrated thatPten-deficient ovarian cancer cells establish an immunosuppressed TIME characterized by increased proportions of M2-like macrophages, GR1+MDSCs in the ascites, and reduced effector CD8+ cytotoxic T-cell function compared withBrca1-deficient cells; further, tumors from mice injected withPten-deficient ID8 cells exhibited an aggressive behavior due to suppressive macrophage dominance in the malignant ascites. In combination with chemotherapy, exogenous STING activation resulted in longer overall survival in mice injected withPten-deficient ID8 cells, reprogrammed intraperitoneal M2-like macrophages derived fromPten-deficient ascites to M1-like phenotype and rescued CD8+ cytotoxic T-cell activation.

Conclusions

This study reveals the importance of considering the influence of cancer cell intrinsic genetic alterations on the TIME for therapeutic selection. We establish the rationale for the optimal incorporation of interferon activating therapies as a novel combination strategy in PTEN-deficient HGSC.

The prognostic impact of PD-L1 and CD8 expression in anal cancer patients treated with chemoradiotherapy

Background

Programmed death-ligand 1 (PD-L1) expression has been shown to be prognostic in many cancer types and used in consideration of checkpoint inhibitor immunotherapy. However, there are very limited and conflicting data on the prognostic impact of PD-L1 in patients with anal squamous cell carcinoma (ASCC). The objectives of this study were to measure the expression of PD-L1 and CD8 in patients with ASCC treated with radical chemoradiotherapy (CRT) and to correlate tumor expression with progression-free survival (PFS) and overall survival (OS).

Methods

Ninety-nine patients with ASCC treated with primary CRT at two tertiary care cancer centers between 2000 and 2013, with available pre-treatment tumors, were included. Tissue microarrays (TMAs) from pre-treatment tumor specimens were stained for PD-L1 and CD8. PD-L1 expression in the tumor and stroma was quantified using HALO image analysis software, and results were interpreted using quantitative methods. The density of CD8 cells within the tumor was interpreted by a trained pathologist semi-quantitatively, using a 0-4 scoring system. Kaplan-Meier analysis with log-rank was used to determine the significance in the association of tumor markers with PFS and OS. Cox multivariate analysis was used to explore independent predictors of PFS and OS.

Results

Of the 99 patients, 63 (64%) had sufficient tumor samples available for full analysis. CD8 high status was documented in 32 of 63 (50.8%) % of cases. PD-L1 expression was positive in 88.9% of cases. Approximately half the patients had tumor PD-L1 ≥ 5%. Patients with tumor PD-L1 ≥ 5% had better OS vs those with lower expression, HR=0.32 (95% CI 0.11-0.87), p=0.027; 10 years OS: 84% for tumor PD-L1 ≥ 5% vs 49% for PD-L1 < 5%. PD-L1 expression was not associated with PFS. On multivariate analysis, tumor PD-L1 ≥ 5% showed a trend to statistical significance for better OS, HR=0.55 (95% CI 0.12- 1.00), p=0.052.

Conclusions

Tumor PD-L1≥5% is associated with OS in patients with ASCC treated with CRT. PD-L1 expression status using this unique cut-point warrants further validation for prognostication in patients with this disease. Future studies are required to determine the benefit of alternative treatment strategies based on PD-L1 status.

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.

Abstract B20: Endometrial cancer molecular risk stratification in endometrioid ovarian cancers: A novel application of precision medicine

Objective: Endometrioid ovarian carcinoma (ENOC) is associated with a generally more favorable prognosis compared to other ovarian carcinoma histotypes. Nonetheless, patients are still treated with a “one size fits all” approach. While tumor staging offers some stratification, the development of personalized treatment concepts remains elusive. Our group has recently validated the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE), to distinguish clinically relevant prognostic groups amongst endometrial carcinomas. ENOC shares risk factors, genomics, and histology with its endometrial counterpart. The aim of our study was to apply and test ProMisE on ENOC.

Methods: ProMisE was applied to 509 ENOC after biomarker-assisted review of ENOC histotype. Cases were aligned into low-risk POLE mutant (POLE), moderate-risk mismatch repair deficient (MMRd), high-risk p53 abnormal (p53abn), and a final moderate-risk category lacking these biomarkers (p53wt). Kaplan-Meier and multivariate survival analysis were performed.

Results: 4% of cases were POLE, 16% MMRd, 71% p53wt, and 10% p53abn. Groups showed distinct progression-free and overall survival (p &lt;0.001), near identical to profiles of endometrial cancers. 5-year PFS was 54% in p53abn, 82% in MMRd, 85% in p53wt, and 100% in POLEmut cases. Median overall survival was reached in p53 mutant cases only. ProMisE classes of ENOC were independent of stage and residual disease in multivariable analysis.

Conclusion: ProMisE risk classification provides additional prognostic information in a large cohort of ENOC. Our findings support introduction of ProMisE-stratified treatment strategies to improve patient care across ENOC. Further, ENOC may benefit from parallel efforts under investigation in endometrial carcinoma.

Citation Format: Pauline Krämer, Aline Talhouk, Tjalling Bosse, Florian Heitz, Naveena Singh, Felix Kommoss, Sara Brucker, Jessica McAlpine, Stefan Kommoss, Martin Koebel, Michael Anglesio. Endometrial cancer molecular risk stratification in endometrioid ovarian cancers: A novel application of precision medicine [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B20.

Expression of L1 retrotransposon open reading frame protein 1 in gynecologic cancers

LINE-1 (L1) retrotransposons are mobile genetic elements capable of "copy-and-pasting" their own sequences into random genomic loci, and one of the proteins it uses to achieve mobility is LINE-1 open reading frame 1 protein (L1ORF1p). L1ORF1p expression is found across many epithelial cancers, including small cohorts of ovarian and endometrial cancers, and is highly expressed in cancers with mutant p53 expressions. Here we aimed to gain insights into L1ORF1p expression levels within specific histotypes of ovarian cancers: high-grade serous (n = 585), low-grade serous (n = 26), clear cell (n = 132), endometrioid (n = 148), and mucinous (n = 32) ovarian cancers, as well as endometrial cancers (n = 607) using tissue microarray (TMA's). We demonstrated that L1ORF1p expression is associated with advanced stage and serous histotype in gynecological cancers. Like previous studies, we found a higher proportion of L1ORF1p expression in cases with aberrant p53 expression. We evaluated the expression of L1ORF1p in serous tubal intraepithelial carcinomas (STICs) (n = 6) and p53 signature lesions (n = 2) in fallopian tubes. Three STIC cases displayed aberrant p53 overexpression with corresponding L1ORF1p expression in the same tissues, but such correlation was not seen in the two p53 signature lesions, suggesting that L1 protein may be expressed after dysplastic transformation. The remaining three STIC cases have TP53 nonsense mutations with absent p53 expression but a strong and clear L1ORF1p expression within the STIC lesions. While L1ORF1p may not be prognostic in gynecological cancers, it may be useful clinically as a diagnostic IHC marker for p53 null STIC lesions and this warrants further investigation.

Abstract B08: Genomics analyses of less common epithelial ovarian cancer subtypes

While the genomics of high-grade serous carcinoma are well-studied in large international consortia, the less common subtypes have been neglected. We have sought to rectify this gap by analyzing international collections of low-grade serous and mucinous ovarian carcinomas and their putative benign and borderline precursors.

Exome sequencing and copy number analysis of low-grade serous carcinomas (n=9) and serous borderline tumours (n=13) and targeted sequencing and copy number analysis in additional carcinomas (n=10) and borderline tumours (n=44) identified recurrent mutations in novel drivers such as EIF1AX and USP9X, as well as the known drivers KRAS, BRAF and NRAS. Copy number changes including 9p and 1p losses were significantly associated with progression from borderline to carcinoma. Exome and targeted sequencing analysis of mucinous carcinomas (GAMuT study) found a surprisingly high proportion (~50%) with TP53 mutations, and mutations in new drivers like RNF43 and ELF3. Despite similarities in early RAS/RAF pathway oncogenic drivers and CDKN2A disruption, the genetics of these two subtypes are otherwise distinct, suggesting differing etiologies and selective pressures.

We also present here the first whole-genome sequencing analysis of a high-grade mucinous ovarian carcinoma collected from multiple sites at autopsy (CASCADE study). The patient, aged just 41 when diagnosed with Stage I mucinous ovarian carcinoma, had a 26-month progression-free interval, including normal CA125 and CA19-9 measurements at 21 months. The primary tumor was mostly borderline in appearance, with only a small focus of carcinoma. At autopsy, the carcinoma was widespread in the body, and whole-genome sequencing data was obtained from deposits in the omentum, iliac lymph node, para-aortic lymph node and upper diaphragm. These data were compared to the primary ovarian tumor and nine other sites sampled at autopsy.

Citation Format: Kylie L. Gorringe, Matthew Wakefield, Sally M. Hunter, Georgina L. Ryland, Dane Cheasley, Michael S. Anglesio, Michael Christie, Raghwa Sharma, Antill Yoland, Simone M. Rowley, Jason Li, Blake Gilks, Prue E. Allan, Andrew N. Stephens, Sumi Ananda, Jan Pyman, Martin Koebel, Jessica McAlpine, Charlie Gourley, David G. Huntsman, Anna deFazio, David DL Bowtell, Ian G. Campbell, Clare Scott. Genomics analyses of less common epithelial ovarian cancer subtypes. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr B08.

Adult lifetime alcohol consumption and invasive epithelial ovarian cancer risk in a population-based case-control study

OBJECTIVE

Meta-analyses report a null association between recent alcohol consumption and ovarian cancer risk. However, because few studies investigated different types of alcohol over adult ages, we investigated adult lifetime and type (beer, wine, spirits) of consumption and risk.

METHODS

Consumption after age 20years was ascertained in 1144 invasive epithelial ovarian cancer cases and 2513 controls in a population-based case-control study (Alberta and British Columbia, Canada, 2001-2012). Non-drinkers consumed any types of alcohol <12 times per year on average. Logistic regression was use to estimate adjusted odds ratios [aOR] and 95% confidence intervals [CIs].

RESULTS

Wine consumption was associated with a risk reduction (aOR=0.67, 95% CI: 0.50-0.88) relative to non-drinkers, but not beer (aOR=1.06, 95% CI: 0.71-1.58) or spirits (aOR=0.98, 95% CI: 0.69-1.39). The reduced risk was stronger for exclusive red wine drinkers (aOR=0.44, 95% CI: 0.19-0.92) than white wine drinkers (aOR=0.79, 95% CI: 0.46-1.34), although most women drank both types of wine. Risk decreased with increasing cumulative consumption of any wine (P-trend<0.05) and was evident for the serous histotype. Wine consumption initiated prior to age 50 was associated with a risk reduction (e.g., at 40-49years, aOR=0.58, 95% CI: 0.42-0.78), but not drinking initiated after 50years of age. For any type, level, or age at initiation of alcohol consumption, we found no increased risks.

CONCLUSIONS

For the moderate consumption in this study, higher levels of wine consumption were generally associated with risk reductions; reductions may be stronger for red wine. Our results suggest that alcohol consumption that is guideline concordant will not increase epithelial ovarian cancer risk.