Context-dependent environmental associations with endometrial cancer histotype and genotype

OBJECTIVE

MLH1 loss due to MLH1 methylation, detected during Lynch syndrome screening, is one of the most common molecular changes in endometrial cancer. It is well established that environmental influences such as nutritional state can impact gene methylation, both in the germline and in a tumor. In colorectal cancer and other cancer types, aging is associated with changes in gene methylation. The objective of this study was to determine if there was an association between aging or body mass index on MLH1 methylation in sporadic endometrial cancer.

METHODS

A retrospective review of patients with endometrial cancer was performed. Tumors were screened for Lynch syndrome via immunohistochemistry, with MLH1 methylation analysis performed when there was loss of MLH1 expression. Clinical information was abstracted from the medical record.

RESULTS

There were 114 patients with mismatch repair deficient tumors associated with MLH1 methylation, and 349 with mismatch repair proficient tumors. Patients with mismatch repair deficient tumors were older than those whose tumors were proficient. Mismatch repair deficient tumors had a higher incidence of lymphatic/vascular space invasion. When stratified by endometrioid grade, associations with body mass index and age became apparent. Patients with endometrioid grades 1 and 2 tumors and somatic mismatch repair deficiency were significantly older, but body mass index was comparable with that of the mismatch repair intact group. For endometrioid grade 3, patient age did not significantly vary between the somatic mismatch repair deficient group and the mismatch repair intact group. In contrast, body mass index was significantly higher in the patients with grade 3 tumors with somatic mismatch repair deficiency.

CONCLUSION

The relationship of MLH1 methylated endometrial cancer with age and body mass index is complex and somewhat dependent on tumor grade. As body mass index is modifiable, it is possible that weight loss induces a 'molecular switch' to alter the histologic characteristics of an endometrial cancer.

Comparative Tumor Microenvironment Analysis of Primary and Recurrent Ovarian Granulosa Cell Tumors

Adult-type granulosa cell tumors (aGCT) are rare ovarian sex cord tumors with few effective treatments for recurrent disease. The objective of this study was to characterize the tumor microenvironment (TME) of primary and recurrent aGCTs and to identify correlates of disease recurrence. Total RNA sequencing (RNA-seq) was performed on 24 pathologically confirmed, cryopreserved aGCT samples, including 8 primary and 16 recurrent tumors. After read alignment and quality-control filtering, DESeq2 was used to identify differentially expressed genes (DEG) between primary and recurrent tumors. Functional enrichment pathway analysis and gene set enrichment analysis was performed using "clusterProfiler" and "GSVA" R packages. TME composition was investigated through the analysis and integration of multiple published RNA-seq deconvolution algorithms. TME analysis results were externally validated using data from independent previously published RNA-seq datasets. A total of 31 DEGs were identified between primary and recurrent aGCTs. These included genes with known function in hormone signaling such as LHCGR and INSL3 (more abundant in primary tumors) and CYP19A1 (more abundant in recurrent tumors). Gene set enrichment analysis revealed that primarily immune-related and hormone-regulated gene sets expression was increased in recurrent tumors. Integrative TME analysis demonstrated statistically significant depletion of cancer-associated fibroblasts in recurrent tumors. This finding was confirmed in multiple independent datasets.

IMPLICATIONS

Recurrent aGCTs exhibit alterations in hormone pathway gene expression as well as decreased infiltration of cancer-associated fibroblasts, suggesting dual roles for hormonal signaling and TME remodeling underpinning disease relapse.

Abstract 2503: Tumor microenvironment composition correlates with relapse in ovarian granulosa cell tumors

Background: Adult-type granulosa cell tumors (AGCT) are rare ovarian sex cord tumors that exhibit near-universal FOXL2 c.C402G (p.Cys134Trp) hotspot mutations. AGCT recurrence is difficult to predict and is almost always incurable after relapse. Little is known about the relationship between intra-tumor immune and stromal composition and AGCT relapse.

Objective: To compare global gene expression profiles between primary and recurrent AGCTs, characterize the tumor microenvironment (TME), and identify correlates of disease recurrence.

Methods: Total RNA sequencing was performed on 24 pathologically confirmed, cryopreserved AGCT samples, including 8 primary and 16 recurrent tumors. Standard methods were applied for read alignment, quality control, and quantification of gene-specific read counts. DESeq2 was used to identify statistically significant (adjusted P-value < 0.05) differentially expressed genes between primary and recurrent tumors with fold change > 2. Gene set enrichment analysis was performed using clusterProfiler. Integrative TME composition de-convolution was performed using multiple published algorithms including CIBERSORTx, quanTIseq, xCell, MCP-counter, and EPIC. TME analysis results were externally validated using data from smaller, previously published RNA sequencing datasets.

Results: Thirty-one genes were identified as differentially expressed between primary and recurrent AGCTs, including NELL2, GDF6, TUBB2B, AQP3. These included genes with known function in hormone signaling such as LHCGR (adjusted P-value = 0.002) and INSL3 (adjusted P-value = 0.017) which were highly expressed in primary tumors and CYP19A1 (adjusted P-value = 0.009) which was highly expressed in recurrent tumors. Gene set enrichment analysis revealed increased expression of hormone-regulated and immune-related gene sets in recurrent tumors. Integrative, multi-platform TME analysis showed recurrent AGCT to exhibit reduced fractions of cancer-associated fibroblasts and enrichment of myeloid lineages such as neutrophils and macrophages.

Conclusions: Recurrent AGCTs exhibit alterations in hormone pathway gene expression as well as decreased infiltration of cancer-associated fibroblasts, suggesting dual roles for hormonal signaling and TME remodeling underpinning disease relapse.

Citation Format: Eleonora Khlebus, Veena K. Vuttaradhi, Thomas Welte, Namrata Khurana, Joseph Celestino, Hannah C. Beird, Curtis Gumbs, Latasha Little, Alejandra Flores Legarreta, Tri Nguyen, Barrett Lawson, Russell R. Broaddus, David M. Gershenson, P. Andrew Futreal, R. Tyler Hillman. Tumor microenvironment composition correlates with relapse in ovarian granulosa cell tumors [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 2503.

Mismatch Repair and Microsatellite Instability Testing for Immune Checkpoint Inhibitor Therapy: ASCO Endorsement of College of American Pathologists Guideline

PURPOSE

The College of American Pathologists (CAP) has developed a guideline on testing for mismatch repair (MMR) and microsatellite instability (MSI) for patients considered for immune checkpoint inhibitor therapy. ASCO has a policy and set of procedures for endorsing clinical practice guidelines that have been developed by other professional organizations.

METHODS

The CAP guideline was reviewed for developmental rigor by methodologists. An ASCO Endorsement Panel subsequently reviewed the content and the recommendations.

RESULTS

The ASCO Endorsement Panel determined that the recommendations from the CAP guideline, published on August 3, 2022, are clear, thorough, and based on the most relevant scientific evidence. ASCO endorses Mismatch Repair and Microsatellite Instability Testing for Immune Checkpoint Inhibitor Therapy: Guideline From the College of American Pathologists in Collaboration With the Association for Molecular Pathology and Fight Colorectal Cancer.

RECOMMENDATIONS

Within the guideline, MMR immunohistochemistry (IHC), MSI polymerase chain reaction, and MSI next-generation sequencing are all recommended testing options for colorectal cancer, MMR-IHC and MSI-polymerase chain reaction for gastroesophageal and small bowel cancer, and only MMR-IHC for endometrial cancer. No recommendation in favor of any testing method over another could be made for any other cancer. Tumor mutational burden was not recommended as a surrogate for DNA MMR deficiency. If MMR deficiency consistent with Lynch syndrome is detected, it should be communicated to the treating physician.Additional information is available at www.asco.org/molecular-testing-and-biomarkers-guidelines.

Mismatch Repair and Microsatellite Instability Testing for Immune Checkpoint Inhibitor Therapy: Guideline From the College of American Pathologists in Collaboration With the Association for Molecular Pathology and Fight Colorectal Cancer

CONTEXT.—

The US Food and Drug Administration (FDA) approved immune checkpoint inhibitor therapy for patients with advanced solid tumors that have DNA mismatch repair defects or high levels of microsatellite instability; however, the FDA provided no guidance on which specific clinical assays should be used to determine mismatch repair status.

OBJECTIVE.—

To develop an evidence-based guideline to identify the optimal clinical laboratory test to identify defects in DNA mismatch repair in patients with solid tumor malignancies who are being considered for immune checkpoint inhibitor therapy.

DESIGN.—

The College of American Pathologists convened an expert panel to perform a systematic review of the literature and develop recommendations. Using the National Academy of Medicine-endorsed Grading of Recommendations Assessment, Development and Evaluation approach, the recommendations were derived from available evidence, strength of that evidence, open comment feedback, and expert panel consensus. Mismatch repair immunohistochemistry, microsatellite instability derived from both polymerase chain reaction and next-generation sequencing, and tumor mutation burden derived from large panel next-generation sequencing were within scope.

RESULTS.—

Six recommendations and 3 good practice statements were developed. More evidence and evidence of higher quality were identified for colorectal cancer and other cancers of the gastrointestinal (GI) tract than for cancers arising outside the GI tract.

CONCLUSIONS.—

An optimal assay depends on cancer type. For most cancer types outside of the GI tract and the endometrium, there was insufficient published evidence to recommend a specific clinical assay. Absent published evidence, immunohistochemistry is an acceptable approach readily available in most clinical laboratories.

Mechanisms of mutant β-catenin in endometrial cancer progression

Endometrial carcinoma (EC) is the most diagnosed gynecological malignancy in Western countries. Both incidence and mortality rates of EC have steadily risen in recent years. Despite generally favorable prognoses for patients with the endometrioid type of EC, a subset of patients has been identified with decreased progression-free survival. Patients in this group are distinguished from other endometrioid EC patients by the presence of exon 3 hotspot mutations in CTNNB1, the gene encoding for the β-catenin protein. β-catenin is an evolutionarily conserved protein with critical functions in both adherens junctions and Wnt-signaling. The exact mechanism by which exon 3 CTNNB1 mutations drive EC progression is not well understood. Further, the potential contribution of mutant β-catenin to adherens junctions' integrity is not known. Additionally, the magnitude of worsened progression-free survival in patients with CTNNB1 mutations is context dependent, and therefore the importance of this subset of patients can be obscured by improper categorization. This review will examine the history and functions of β-catenin, how these functions may change and drive EC progression in CTNNB1 mutant patients, and the importance of this patient group in the broader context of the disease.

DNA Damage Repair Classifier Defines Distinct Groups in Hepatocellular Carcinoma

Simple Summary

DNA repair pathways have been implicated in hepatocellular carcinoma outcomes. We found that hepatocellular carcinomas (HCC) could be separated into two groups (high and low) based on the overall expression of genes involved in DNA repair. Among the low repair group, there were three subgroups, one of which shared features of the high repair group. Given the important role of liver in metabolism and detoxification and its regenerative capacity, proliferation and DNA damage responses are critical in subdividing major biological categories of liver tumors. High repair samples showed more proliferative and regenerative signatures and had poorer outcomes versus the low repair that were more associated with the genes involved in normal liver biology. These biological groups suggest that dysregulation in endogenous liver processes promotes a pro-tumorigenic microenvironment that may facilitate tumor progression or identify tumors that require more substantial clinical intervention.

Abstract

DNA repair pathways have been associated with variability in hepatocellular carcinoma (HCC) clinical outcomes, but the mechanism through which DNA repair varies as a function of liver regeneration and other HCC characteristics is poorly understood. We curated a panel of 199 genes representing 15 DNA repair pathways to identify DNA repair expression classes and evaluate their associations with liver features and clinicopathologic variables in The Cancer Genome Atlas (TCGA) HCC study. We identified two groups in HCC, defined by low or high expression across all DNA repair pathways. The low-repair group had lower grade and retained the expression of classical liver markers, whereas the high-repair group had more clinically aggressive features, increased p53 mutant-like gene expression, and high liver regenerative gene expression. These pronounced features overshadowed the variation in the low-repair subset, but when considered separately, the low-repair samples included three subgroups: L1, L2, and L3. L3 had high DNA repair expression with worse progression-free (HR 1.24, 95% CI 0.81–1.91) and overall (HR 1.63, 95% CI 0.98–2.71) survival. High-repair outcomes were also significantly worse compared with the L1 and L2 groups. HCCs vary in DNA repair expression, and a subset of tumors with high regeneration profoundly disrupts liver biology and poor prognosis.

Adjuvant treatment in early-stage endometrial cancer: context-dependent impact of somatic CTNNB1 mutation on recurrence-free survival

OBJECTIVE

The primary objective of this study was to determine whether women whose tumors harbor a somatic CTNNB1 mutation have longer recurrence-free survival if they receive traditional adjuvant therapy strategies compared with those who do not.

METHODS

A retrospective, stage I endometrial cancer cohort from MD Anderson Cancer Center was assessed. Clinical and pathological characteristics and type of adjuvant therapy (cuff brachytherapy, pelvic radiation, chemotherapy) were obtained by review of medical records. CTNNB1 exon 3 sequencing was performed. Summary statistics were calculated, and recurrence-free survival was measured using the Kaplan-Meier product-limit estimator.

RESULTS

The analysis included 253 patients, 245 with information regarding adjuvant therapy. Most patients had tumors of endometrioid histology (210/253, 83%) with superficial myometrial invasion (197/250, 79%) and no lymphatic/vascular space invasion (168/247, 68%). Tumor CTNNB1 mutations were present in 45 (18%) patients. Patients receiving adjuvant therapy were more likely to have higher-grade tumors, non-endometrioid histology, deep myometrial invasion, and lymphatic/vascular invasion. For patients with low-risk features not receiving adjuvant therapy, the presence of CTNNB1 mutation did not significantly impact recurrence-free survival (11.3 years wild-type vs 8.1 years mutant, p=0.65). The cohort was then limited to intermediate-risk tumors, defined as endometrioid histology of any grade with deep myometrial invasion and/or lymphatic/vascular space invasion. When recurrence-free survival was stratified by CTNNB1 mutation status and adjuvant therapy, patients with CTNNB1 mutations and no adjuvant therapy had the shortest recurrence-free survival at 1.6 years, followed by patients with CTNNB1 mutations who received adjuvant therapy (4.0 years), and wild-type CTNNB1 with and without adjuvant therapy (8.5 and 7.2 years, respectively) (comparison for all four groups, p=0.01).

CONCLUSION

In patients with intermediate-risk endometrioid endometrial cancers, the use of adjuvant therapy was associated with an improvement in recurrence-free survival for patients with tumor mutations in CTNNB1.

Clinical and Financial Implications of Second-Opinion Surgical Pathology Review

OBJECTIVES

Second-opinion pathology review identifies clinically significant diagnostic discrepancies for some patients. Discrepancy rates and laboratory-specific costs in a single health care system for patients referred from regional affiliates to a comprehensive cancer center ("main campus") have not been reported.

METHODS

Main campus second-opinion pathology cases for 740 patients from eight affiliated hospitals during 2016 to 2018 were reviewed. Chart review was performed to identify changes in care due to pathology review. To assess costs of pathology interpretation, reimbursement rates for consultation Current Procedural Terminology billing codes were compared with codes that would have been used had the cases originated at the main campus.

RESULTS

Diagnostic discrepancies were identified in 104 (14.1%) patients, 30 (4.1%) of which resulted in a change in care. In aggregate, reimbursement for affiliate cases was 65.6% of the reimbursement for the same cases had they originated at the main campus. High-volume organ systems with low relative consultation reimbursement included gynecologic, breast, and thoracic.

CONCLUSIONS

Preventable diagnostic errors are reduced by pathology review for patients referred within a single health care system. Although the resulting changes in care potentially lead to overall cost savings, the financial value of referral pathology review could be improved.

Clinical and Functional Characterization of Atypical KRAS/NRAS Mutations in Metastatic Colorectal Cancer

PURPOSE

Mutations in KRAS/NRAS (RAS) predict lack of anti-EGFR efficacy in metastatic colorectal cancer (mCRC). However, it is unclear if all RAS mutations have similar impact, and atypical mutations beyond those in standard guidelines exist.

EXPERIMENTAL DESIGN

We reviewed 7 tissue and 1 cell-free DNA cohorts of 9,485 patients to characterize atypical RAS variants. Using an in vitro cell-based assay (functional annotation for cancer treatment), Ba/F3 transformation, and in vivo xenograft models of transduced isogenic clones, we assessed signaling changes across mutations.

RESULTS

KRAS exon 2, extended RAS, and atypical RAS mutations were noted in 37.8%, 9.5%, and 1.2% of patients, respectively. Among atypical variants, KRAS L19F, Q22K, and D33E occurred at prevalence ≥0.1%, whereas no NRAS codon 117/146 and only one NRAS codon 59 mutation was noted. Atypical RAS mutations had worse overall survival than RAS/BRAF wild-type mCRC (HR, 2.90; 95% confidence interval, 1.24-6.80; P = 0.014). We functionally characterized 114 variants with the FACT assay. All KRAS exon 2 and extended RAS mutations appeared activating. Of 57 atypical RAS variants characterized, 18 (31.6%) had signaling below wild-type, 23 (40.4%) had signaling between wild-type and activating control, and 16 (28.1%) were hyperactive beyond the activating control. Ba/F3 transformation (17/18 variants) and xenograft model (7/8 variants) validation was highly concordant with FACT results, and activating atypical variants were those that occurred at highest prevalence in clinical cohorts.

CONCLUSIONS

We provide best available evidence to guide treatment when atypical RAS variants are identified. KRAS L19F, Q22K, D33E, and T50I are more prevalent than many guideline-included RAS variants and functionally relevant.

Inactivating Mutations of the IK Gene Weaken Ku80/Ku70-Mediated DNA Repair and Sensitize Endometrial Cancer to Chemotherapy

IK is a mitotic factor that promotes cell cycle progression. Our previous investigation of 271 endometrial cancer (EC) samples from the Cancer Genome Atlas (TCGA) dataset showed IK somatic mutations were enriched in a cluster of patients with high-grade and high-stage cancers, and this group had longer survival. This study provides insight into how IK somatic mutations contribute to EC pathophysiology. We analyzed the somatic mutational landscape of IK gene in 547 EC patients using expanded TCGA dataset. Co-immunoprecipitation and mass spectrometry were used to identify protein interactions. In vitro and in vivo experiments were used to evaluate IK's role in EC. The patients with IK-inactivating mutations had longer survival during 10-year follow-up. Frameshift and stop-gain were common mutations and were associated with decreased IK expression. IK knockdown led to enrichment of G2/M phase cells, inactivation of DNA repair signaling mediated by heterodimerization of Ku80 and Ku70, and sensitization of EC cells to cisplatin treatment. IK/Ku80 mutations were accompanied by higher mutation rates and associated with significantly better overall survival. Inactivating mutations of IK gene and loss of IK protein expression were associated with weakened Ku80/Ku70-mediated DNA repair, increased mutation burden, and better response to chemotherapy in patients with EC.

Loss of CD73 shifts transforming growth factor-β1 (TGF-β1) from tumor suppressor to promoter in endometrial cancer

In many tumors, CD73 (NT5E), a rate-limiting enzyme in adenosine biosynthesis, is upregulated by TGF-β and drives tumor progression. Conversely, CD73 is downregulated in endometrial carcinomas (EC) despite a TGF-β-rich environment. Through gene expression analyses of normal endometrium samples of the uterine cancer TCGA data set and genetic and pharmacological studies, we discovered CD73 loss shifts TGF-β1 from tumor suppressor to promoter in EC. TGF-β1 upregulated CD73 and epithelial integrity in vivo in the normal endometrium and in vitro in early stage EC cells. With loss of CD73, TGF-β1-mediated epithelial integrity was abrogated. EC cells developed TGF-β1-mediated stress fibers and macromolecule permeability, migration, and invasion increased. In human tumors, CD73 is downregulated in deeply invasive stage I EC. Consistent with shifting TGF-β1 activity, CD73 loss increased TGF-β1-mediated canonical signaling and upregulated cyclin D1 (CCND1) and downregulated p21 expression. This shift was clinically relevant, as CD73^Low/CCND1^High expression associated with poor tumor differentiation, increased myometrial and lymphatic/vascular space invasion, and patient death. Further loss of CD73 in CD73^Low expressing advanced stage EC cells increased TGF-β-mediated stress fibers, signaling, and invasiveness, whereby adenosine A1 receptor agonist, CPA, dampened TGF-β-mediated invasion. These data identify CD73 loss as essential for shifting TGF-β activity in EC.

Long-term Patterns of Excess Mortality among Endometrial Cancer Survivors

Purpose of the study: Examining long-term patterns of mortality among cancer survivors compared to the general population may inform planning for surveillance and follow-up care. We investigated excess mortality after endometrial cancer using conditional relative survival estimates and standardized mortality ratios (SMRs). Methods: Women diagnosed with endometrial cancer during 2000–2017 (N = 183,153) were identified in the Surveillance, Epidemiology, and End Results (SEER) database. SMRs were calculated as observed deaths among endometrial cancer survivors over expected deaths among demographically similar women in the general U.S. population. Five-year relative survival was estimated at diagnosis and each additional year survived up to 12 years post-diagnosis, conditional on survival up to that year. Results: For the full cohort, 5-year relative survival was 87.7%, 96.2%, and 97.1% at 1, 5, and 10 years post- diagnosis. respectively. Conditional 5-year relative survival first exceeded 95%, reflecting minimal excess mortality compared to the general population, at 4 years post-diagnosis overall, but occurred later for Black women (8 years) compared to White (4 years), and also later for women with regional/distant stage, grade 3 disease, or non- endometrioid histology. The overall SMR for all-cause mortality decreased from 5.90 (95% CI: 5.81–5.99) in the first year after diagnosis to 1.16 (95% CI: 1.13–1.19) at 10+ years; SMRs were consistently higher for non-White women and those with higher stage or grade disease. Conclusions: Overall, endometrial cancer survivors had only a small survival deficit beyond 4 years post- diagnosis. However, excess mortality was greater in magnitude and persisted longer into survivorship for Black women and those with more advanced disease.

Long-term Patterns of Excess Mortality among Endometrial Cancer Survivors

BACKGROUND

We investigated excess mortality after endometrial cancer using conditional relative survival estimates and standardized mortality ratios (SMR).

METHODS

Women diagnosed with endometrial cancer during 2000-2017 (N = 183,153) were identified in the Surveillance Epidemiology and End Results database. SMRs were calculated as observed deaths among endometrial cancer survivors over expected deaths among demographically similar women in the general U.S.

POPULATION

Five-year relative survival was estimated at diagnosis and each additional year survived up to 12 years post-diagnosis, conditional on survival up to that year.

RESULTS

For the full cohort, 5-year relative survival was 87.7%, 96.2%, and 97.1% at 1, 5, and 10 years post-diagnosis, respectively. Conditional 5-year relative survival first exceeded 95%, reflecting minimal excess mortality compared with the general population, at 4 years post-diagnosis overall. However, in subgroup analyses, conditional relative survival remained lower for Black women (vs. White) and for those with regional/distant stage disease (vs. localized) throughout the study period. The overall SMR for all-cause mortality decreased from 5.90 [95% confidence interval (CI), 5.81-5.99] in the first year after diagnosis to 1.16 (95% CI, 1.13-1.19) at 10+ years; SMRs were consistently higher for non-White women and for those with higher stage or grade disease.

CONCLUSIONS

Overall, endometrial cancer survivors had only a small survival deficit beyond 4 years post-diagnosis. However, excess mortality was greater in magnitude and persisted longer into survivorship for Black women and for those with more advanced disease.

IMPACT

Strategies to mitigate disparities in mortality after endometrial cancer will be needed as the number of survivors continues to increase.

Endometrial biomarkers in premenopausal women with obesity: an at-risk cohort

BACKGROUND

Obesity is a well-known risk factor for endometrial cancer, but the mechanisms of obesity-related carcinogenesis are not well defined, particularly for premenopausal women. With the continuing obesity epidemic, increases in the incidence of endometrial cancer and a younger age of diagnosis are often attributed to a hyperestrogenic state created by hormone production in adipose tissue, but significant knowledge gaps remain. The balance of estrogen-responsive signals has not been defined in the endometrium of premenopausal women with obesity, where obesity may not create hyperestrogenism in the context of ovaries being the primary source of estrogen production. Obesity is associated with a state of low-grade, chronic inflammation that can promote tumorigenesis, and it is also known that hormonal changes alter the immune microenvironment of the endometrium. However, limited research has been conducted on endometrial immune-response changes in women who have an increased risk for cancer due to obesity.

OBJECTIVE

Endometrial estrogen-regulated biomarkers, previously shown to be dysregulated in endometrial cancer, were evaluated in a cohort of premenopausal women to determine if obesity is associated with differences in the biomarker expression levels, which might reflect an altered risk of developing cancer. The expression of a multiplexed panel of immune-related genes was also evaluated for expression differences related to obesity.

STUDY DESIGN

Premenopausal women with a body mass index of ≥30 kg/m² (n=97) or a body mass index of ≤25 kg/m² (n=33) were prospectively enrolled in this cross-sectional study, which included the assessment of serum metabolic markers and a timed endometrial biopsy for pathologic evaluation, hormone-regulated biomarker analysis, and immune response gene expression analysis. Medical and gynecologic histories were obtained. Endometrial gene expression markers were also compared across the body mass index groups in a previous cohort of premenopausal women with an inherited cancer risk (Lynch syndrome).

RESULTS

In addition to known systemic metabolic differences, histologically normal endometria from women with obesity showed a decrease in gene expression of progesterone receptor (P=.0027) and the estrogen-induced genes retinaldehyde dehydrogenase 2 (P=.008), insulin-like growth factor 1 (P=.016), and survivin (P=.042) when compared with women without obesity. The endometrial biomarkers insulin-like growth factor 1, survivin, and progesterone receptor remained statistically significant in multivariate linear regression models. In contrast, women with obesity and Lynch syndrome had an increased expression of insulin-like growth factor 1 (P=.017). There were no differences in endometrial proliferation, and limited endometrial immune differences were observed.

CONCLUSION

When comparing premenopausal women with and without obesity in the absence of endometrial pathology or an inherited cancer risk, the expression of the endometrial biomarkers does not reflect a local hyperestrogenic environment, but it instead reflects a decreased cancer risk profile that may be indicative of a compensated state. In describing premenopausal endometrial cancer risk, it may be insufficient to attribute a high-risk state to obesity alone; further studies are warranted to evaluate individualized biomarker profiles for differences in the hormone-responsive signals or immune response. In patients with Lynch syndrome, the endometrial biomarker profile suggests that obesity further increases the risk of developing cancer.

Abstract PR005: CD73 sequestering mutant β-catenin at the membrane explains recurrence in CTNNB1 mutant endometrial cancer

Somatic missense mutations in exon 3 of CTNNB1 are associated with significantly worse recurrence-free survival in patients with low grade, early stage endometrioid-type endometrial carcinoma (EEC). CTNNB1 encodes for β-catenin, an integral protein in Wnt signaling and core member of E-cadherin-catenin cell-cell adhesions. Although CTNNB1 mutation identifies patients at higher risk for recurrence, not all patients will recur. Nuclear expression of β-catenin protein in CTNNB1-mutated EEC is not robust as is normally seen in other CTNNB1-mutated cancers such as desmoid tumor and colon cancer. This suggests cancer-specific molecular mechanisms may regulate mutant β-catenin in EEC. Previously, we identified a cancer-specific role for CD73, a cell surface 5’nuclotidase, in EEC. CD73 is downregulated and its loss associates with poor survival. Notably, CD73 inhibits tumor progression by increasing the localization of wild-type β-catenin to the membrane. Through fractionation and co-immunoprecipitation studies, using a highly homologous (97.4% identical; 100% identical in exon 3 (UniPort)) Xenopus exon 3 CTNNB1 mutant expressed in HEC-1-A cells, and human tumor data we provide evidence that CD73 sequesters mutant β-catenin at the membrane with E-cadherin, subsequently limiting its nuclear translocation. EEC patients with CTNNB1 mutation and low CD73 expression have increased incidence of recurrence (n = 29). CD73 levels were not significantly different with clinical stage or lymphatic and vascular space invasion, suggesting that CD73 expression independently predicts disease recurrence in patients with CTNNB1 mutant tumors. CTNNB1 mutations in EEC rarely occur in the region of the β-catenin protein that binds to E-cadherin. Thus, mechanisms regulating the movement of wild-type β-catenin to the membrane would be expected to be able to localize mutant β-catenin to the membrane regardless of exon 3 mutation. Immunohistochemistry studies of CTNNB1 mutant tumors (n = 11) show a strong association between CD73 expression and β-catenin localization in cancer cells. Cancer cells expressing membrane CD73 largely express β-catenin at the membrane. Whereas, in cancer cells with CD73 loss or cytoplasmic CD73 expression, β-catenin nuclear staining is increased. While these data are preliminary, CD73 sequestering mutant β-catenin to the membrane suggests a molecular mechanism for why certain patients with CTNNB1 mutant tumors recur. Accordingly, CD73 may serve as a biomarker for identifying patients for more aggressive clinical management to prevent recurrence.

Citation Format: Jessica L. Bowser, Katherine C. Kurnit, Luan H. Phan, Jerry B. Harvey, Jiping Feng, SuSu Xie, Andrew B. Gladden, Pierre D. McCrea, Russell R. Broaddus. CD73 sequestering mutant β-catenin at the membrane explains recurrence in CTNNB1 mutant endometrial cancer [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 PR005.

Abstract IA008: Mismatch repair deficiency and survival in stage I endometrial cancer

The importance of testing for DNA mismatch repair defects and high levels of tumor microsatellite instability (MSI) is established for screening colorectal and endometrial cancers for Lynch Syndrome and advanced solid tumor malignancies for treatment with checkpoint inhibitors. Therefore, accurate clinical assays are necessary to identify DNA mismatch repair defects and patients with cancers with high levels of MSI. While defects in DNA mismatch repair identified by immunohistochemistry may often overlap with tumor microsatellite instability as identified by PCR-based assays, the two molecular events are not synonymous and can be discordant in individual cancers. Cancers outside of the GI tract may have loss of DNA mismatch repair proteins but may have more subtle microsatellite instability or even be microsatellite stable. The College of American Pathologists has established an expert guideline committee to help navigate some of the clinical testing issues when trying to detect defects in DNA mismatch repair and MSI in cancers. In addition to these established clinical uses of DNA mismatch repair and MSI, their use as a prognostic biomarker for endometrial cancer is emerging. Data suggest that specific environmental factors may interact with DNA mismatch repair, causing a more variable phenotype in cancers with loss of DNA mismatch repair.

Citation Format: Russell R. Broaddus. Mismatch repair deficiency and survival in stage I endometrial cancer [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 IA008.

Evaluating Mismatch Repair/Microsatellite Instability Status Using Cytology Effusion Specimens to Determine Eligibility for Immunotherapy

CONTEXT.—

The approval of pembrolizumab for treatment of patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) advanced cancers has led to increased requests for MSI and/or MMR immunoperoxidase (IPOX) testing. Diagnoses for patients with advanced-stage cancer are frequently made from cytology specimens.

OBJECTIVE.—

To investigate the feasibility of using cell block (CB) preparations of effusions for MMR IPOX evaluation.

DESIGN.—

Surgical pathology cases of colorectal and endometrial carcinomas with known MMR/MSI status and matched effusions with available CBs were identified. Cell block sections were evaluated for adequacy and stained with MMR IPOX (MSH2, MSH6, MLH1, and PMS2). The CBs were reviewed, the number of tumor cells quantified, and MMR IPOX was interpreted as retained, lost, suboptimal, or noncontributory.

RESULTS.—

We identified 748 cases with MMR/MSI testing on surgical specimens having matched effusions. Of these, 131 cases (17.5%) had an available CB and 53 were deemed adequate for MMR IPOX staining. MMR IPOX results between effusion CBs and surgical pathology specimens were concordant in 45 of 53 (85%), inconclusive in 6 of 53 (11%), and discordant in 2 of 53 (4%) cases.

CONCLUSIONS.—

There was high concordance of MMR IPOX testing between cytologic and surgical specimens, with no false-positive and 2 false-negative CB results. Limited tumor cells, staining in cells indefinite as tumor, tumor staining heterogeneity, and lack of internal control staining were problematic in some cases. Our findings indicate that cytologic effusion specimens may be suitable substrates for MMR IPOX biomarker testing; however, inconclusive cases need to be interpreted with caution.

Variable Expression of MSH6 in Endometrial Carcinomas With Intact Mismatch Repair and With MLH1 Loss Due to MLH1 Methylation

Immunohistochemistry for mismatch repair proteins MLH1, MSH2, MSH6, and PMS2 is an effective screen to detect individuals at risk for Lynch syndrome. College of American Pathologists guidelines stipulate that protein expression should be reported as present versus absent, as most patients with germline mutations in a mismatch repair gene have complete loss of protein expression in tumor cells. A similar approach is employed to screen for cancer patients eligible for immune checkpoint blockade. This "all or none" interpretive approach ignores substantial evidence that mismatch repair may be more finely regulated by other mechanisms. We have observed clinically that MSH6 expression is variable, even in carcinomas that are overall considered positive for MSH6 expression. A proof-of-principle study was therefore designed to more rigorously quantify the protein expression of MSH6 and its binding partner, MSH2, using image analysis applied to age-matched endometrioid grade 2 subsets that were either mismatch repair intact or MLH1-deficient due to MLH1 gene methylation. In both endometrioid groups, MSH6 expression was significantly lower than MSH2 expression. MSH6 expression increased in higher grade, mismatch repair intact serous carcinomas, but it was still significantly lower than that for MSH2. MSH2 expression was consistently high across the 3 different tumor groups. These results suggest that MSH6 expression is subject to wide fluctuations in expression, even when overall its expression is considered intact. While such fluctuations are likely not relevant for Lynch syndrome screening, they may be more impactful when considering patients eligible for immune checkpoint blockade.

Utilization of cytology smears improves success rates of RNA-based next-generation sequencing gene fusion assays for clinically relevant predictive biomarkers

BACKGROUND

The use of RNA-based next-generation sequencing (NGS) assays to detect gene fusions for targeted therapy has rapidly become an essential component of comprehensive molecular profiling. For cytology specimens, the cell block (CB) is most commonly used for fusion testing; however, insufficient cellularity and/or suboptimal RNA quality are often limiting factors. In the current study, the authors evaluated the factors affecting RNA fusion testing in cytology and the added value of smears in cases with a suboptimal or inadequate CB.

METHODS

A 12-month retrospective review was performed to identify cytology cases that were evaluated by a targeted RNA-based NGS assay. Samples were sequenced by targeted amplicon-based NGS for 51 clinically relevant genes on a proprietary platform. Preanalytic factors and NGS quality parameters were correlated with the results of RNA fusion testing.

RESULTS

The overall success rate of RNA fusion testing was 92%. Of the 146 cases successfully sequenced, 14% had a clinically relevant fusion detected. NGS testing success positively correlated with RNA yield (P = .03) but was independent of the tumor fraction, the tumor size, or the number of slides used for extraction. CB preparations were adequate for testing in 45% cases, but the inclusion of direct smears increased the adequacy rate to 92%. There was no significant difference in testing success rates between smears and CB preparations.

CONCLUSIONS

The success of RNA-based NGS fusion testing depends on the quality and quantity of RNA extracted. The use of direct smears significantly improves the adequacy of cytologic samples for RNA fusion testing for predictive biomarkers.

Pathologic distribution at the time of interval tumor reductive surgery informs personalized surgery for high-grade ovarian cancer

INTRODUCTION

The surgical approach for interval debulking surgery after neoadjuvant chemotherapy has been extrapolated from primary tumor reductive surgery for high-grade ovarian cancer. The study objective was to compare pathologic distribution of malignancy at interval debulking surgery versus primary tumor reductive surgery.

METHODS

Patients with a diagnosis of high-grade serous or mixed, non-mucinous, epithelial ovarian, fallopian tube or primary peritoneal cancer who underwent neoadjuvant chemotherapy or primary tumor reductive surgery and had at least 6 months of follow-up were identified through tumor registry at a single institution from January 1995 to April 2016. Pathologic involvement of organs was categorized as macroscopic, microscopic, or no tumor. Statistical analyses included Mann-Whitney and Fisher's exact tests.

RESULTS

Of 918 patients identified, 366 (39.9%) patients underwent interval debulking surgery and 552 (60.1%) patients underwent primary tumor reductive surgery. Median age was 62.3 years (range 25.3-92.5). The majority of patients in the interval debulking surgery group were unstaged (261, 71.5%). In the patients who had a primary tumor reductive surgery, 406 (74.6%) had stage III disease. In both groups, the majority of patients had serous histology: 325 (90%) and 435 (78.8%) in the interval debulking and primary tumor reductive surgery groups, respectively. There was a statistically significant difference between disease distribution on the uterus between the groups; 31.4% of the patients undergoing interval debulking surgery had no evidence of uterine disease compared with 22.1% of primary tumor reductive surgery specimens (p<0.001). In the adnexa, there was macroscopic disease present in 253 (69.2%) and 482 (87.4%) of cases in the interval vs primary surgery groups, respectively (p<0.001). Within the omentum, no tumor was present in the omentum in 52 (14.2%) in the interval surgery group versus 91 (16.5%) in the primary surgery group (p<0.001). In the interval surgery group, there was no tumor involving the small and large bowel in 49 (13.4%) and 28 (7.7%) pathologic specimens, respectively. This was statistically significantly different from the small and large bowel in the primary surgery group, of which there was no tumor in 20 (3.6%, p<0.001) and 16 (2.9%, p<0.001) of cases, respectively.

CONCLUSION

In patients undergoing interval debulking surgery, there was less macroscopic involvement of tumor in the uterus, adnexa and bowel compared with patients undergoing primary cytoreductive surgery.

Pten and Dicer1 loss in the mouse uterus causes poorly differentiated endometrial adenocarcinoma

Endometrial cancer remains the most common gynecological malignancy in the United States. While the loss of the tumor suppressor, PTEN (phosphatase and tensin homolog), is well studied in endometrial cancer, recent studies suggest that DICER1, the endoribonuclease responsible for miRNA genesis, also plays a significant role in endometrial adenocarcinoma. Conditional uterine deletion of Dicer1 and Pten in mice resulted in poorly differentiated endometrial adenocarcinomas, which expressed Napsin A and HNF1B (hepatocyte nuclear factor 1 homeobox B), markers of clear-cell adenocarcinoma. Adenocarcinomas were hormone-independent. Treatment with progesterone did not mitigate poorly differentiated adenocarcinoma, nor did it affect adnexal metastasis. Transcriptomic analyses of DICER1 deleted uteri or Ishikawa cells revealed unique transcriptomic profiles and global miRNA downregulation. Computational integration of miRNA with mRNA targets revealed deregulated let-7 and miR-16 target genes, similar to published human DICER1-mutant endometrial cancers from TCGA (The Cancer Genome Atlas). Similar to human endometrial cancers, tumors exhibited dysregulation of ephrin-receptor signaling and transforming growth factor-beta signaling pathways. LIM kinase 2 (LIMK2), an essential molecule in p21 signal transduction, was significantly upregulated and represents a novel mechanism for hormone-independent pathogenesis of endometrial adenocarcinoma. This preclinical mouse model represents the first genetically engineered mouse model of poorly differentiated endometrial adenocarcinoma.

Abstract 428: The role of Mig-6 as a tumor suppressor in metastatic and recurrent endometrial cancer

Endometrial cancer is the most common gynecologic malignancy with an estimated 63,230 new cases in 2018. Although early-stage and low grade endometrioid endometrial cancers (EEC) generally exhibit a favorable prognosis, 10-15% of tumors recur within 5 years with poor treatment outcomes and low survival rates. Therefore, there is an urgent obligation to explore the mechanism of tumor metastasis and recurrence to further elucidate the progression of EEC. Mitogen inducible gene 6 (MIG-6) plays a tumor suppressor role in endometrial cancer. Ablation of Mig-6 in the murine uterus leads to the development of endometrial hyperplasia and E2-induced EEC. However, how MIG-6 suppresses tumorigenesis and metastasis in EEC is unclear. We have developed a genetically engineered mouse model for metastatic and recurrent EEC that implicates coexistent Pten and Mig-6 mutations in EEC. We also added a double-fluorescent Cre reporter to our EEC mouse model to distinguish EEC from surrounding normal tissues. In Pgrcre/+Rosa26mTmG mice, the Pgr-positive uterine cells express GFP, while Pgr-negative cells express membrane-targeted tandem dimer Tomato. The ablation of both Mig-6 and Pten in the uterus (Pgrcre/+Mig-6f/fPtenf/f; Mig-6d/dPtend/d) dramatically accelerated the development of EEC compared to single ablation of either gene. Importantly, Pten mutation is not sufficient for distant metastasis, but mice with concurrent ablation of Mig-6 and Pten develop distant metastasis. After hysterectomy at stage I of EEC, 62% of Mig-6d/dPtend/d mice (5/8) developed recurrence of EEC in the abdomen and lung. Cholesterol metabolism plays a significant role in cancer metastasis, and Mig-6 plays a critical role in the regulation of cholesterol homeostasis and bile acid synthesis. The ingenuity pathway analysis revealed that cholesterol biosynthesis was the most significantly changed pathway in the endometrial hyperplasia from 2-week-old Mig-6d/dPtend/d mice compared with Ptend/d mice. We found 67 and 18 significantly increased or decreased transcripts, respectively, that are related cholesterol biosynthesis. HMG-coA reductase inhibitors, commonly known as statins, account for the great majority of cholesterol-lowering drug use. However, little is known about the association between statin use and incidence of most types of cancers. To determine the effect of statins on tumorigenesis of EEC in Mig-6d/dPtend/d mice, the mutant mice were treated with atorvastatin (10mg/kg/day oral administration) or vehicle for 2 months. Treatment with statins significantly reduced development and progression of EEC in Mig-6d/dPtend/d mice compared to the vehicle group. Our results demonstrate that Mig-6 suppresses metastasis and recurrence in EEC with Pten mutation by inhibiting cholesterol biosynthesis. Research reported in this publication was supported by The Mary Kay Foundation 2019 research grant.

Citation Format: Tae Hoon Kim, Ryan M. Marquardt, Russell R. Broaddus, Jae-Wook Jeong. The role of Mig-6 as a tumor suppressor in metastatic and recurrent endometrial cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 428.

Abstract 3421: Identifying mechanisms of immune evasion in microsatellite instable endometrial cancers

Inherited or sporadic defects in mismatch repair genes (MLH1, MSH2, MSH6, and PSM2) can lead to microsatellite instable (MSI) tumors, most commonly colon, endometrial or gastric tumors. High mutation rates in MSI tumors have been associated with greater immunogenicity, but these tumors can evade immune response. Recently developed mouse models of MSI endometrial cancer (EC) were used to evaluate immune surveillance mechanisms.

Uterine-targeted MSH2 knockout (PR-Cre+MSH2flox/flox) mice were characterized and determined that 22% of mice develop spontaneous EC by 12-16 months of age. Microsatellite instability was evaluated by PCR. Immune infiltration was quantified by immunohistochemistry (IHC) using FoxP3 (Tregs), CD11b (myeloid cells) and CD8 (tumor infiltrating lymphocytes, TILs) antibodies. Tumors were divided into TILHigh and TILLow (&lt;5 TIL/mm2). Comprehensive transcriptome analysis of tumor and normal controls was performed using the Affymetrix Clariom D assay. A subset of candidate gene changes were validated by RT-PCR and at the protein level by IHC. Cell lines were generated from spontaneous tumors and used for orthotopic syngeneic tumor studies of advanced EC. Immune infiltration in orthotopic tumors was characterized using flow cytometry.

All endometrial tumors from PR-Cre+MSH2flox/flox mice were MSI and included endometrioid, serous, and mixed histologies. Tumors showed varying degrees of immune infiltrate, irrespective of histology. Of 7 tumors, 4 (57%) were TILHigh and 3 (43%) were TILLow. Transcriptome analysis showed TILHigh tumors upregulated innate immunity related pathways including, pattern recognition-associated factors, Type I IFN signaling molecules and CXCL5. Activation of adaptive immunity was observed by an increase in T cell chemoattractants, CXCL9 and CCL21. TILHigh tumors displayed at least a 2-fold increase in MHC class I molecules and CD86 needed for T cell activation. IL1A, CSF1, and TGFB2 (cytokines involved in immunosuppressive cell recruitment and induction) were also highly expressed. IHC confirmed co-localization of TILs with myeloid cells and Tregs in TILHigh tumors. TILLow tumors had decreased expression of several members in the IFN family responsible for initiating innate responses. Primary cell lines from TILHigh and TILLow tumors used in an orthotopic syngeneic mouse model retained the immune profile of the original tumor.

Understanding mechanisms of immune evasion is critical for improving immunotherapy. This model of MSI EC reflects the spectrum of immunogenicity observed in clinical studies. TILHigh tumors express a wide range of factors involved in innate and adaptive anti-tumor responses, while TILLow tumors lack key mediators needed for immune activation. These new models for MSI EC will be essential to test the efficacy of immunotherapies and study mechanisms of resistance.

Citation Format: Brenda Melendez, Emily Hinchcliff, Nisha Gokul, Elizabeth Whitley, Russell R. Broaddus, Rosemarie E. Schmandt, Karen H. Lu, Melinda S. Yates. Identifying mechanisms of immune evasion in microsatellite instable endometrial cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3421.

Identification of biomarkers of immune checkpoint blockade efficacy in recurrent or refractory solid tumor malignancies

Patients with advanced solid malignancies recurrent or resistant to standard therapy have limited treatment options. The role of molecular biomarkers for predicting immune checkpoint blockade (ICB) efficacy are not well characterized in these patients. Tumor mutational profiles of 490 patients with a variety of advanced solid tumors enrolled in a prospective protocol were analyzed to identify prognostic and predictive biomarkers. ICB therapy was defined as treatment with any CTLA-4, PD-1, and/or PD-L1 monoclonal antibody. ICB treatment was associated with significantly improved overall survival compared to non-ICB therapy. Multivariate regression analysis including the two variables of tumor mutation burden (TMB) and ICB, and their interaction term, showed favorable survival associated with ICB, unfavorable survival associated with TMB without ICB treatment, and improved outcome with increasing TMB in ICB treated patients. Tumor TP53 mutation was associated with worse survival, but these patients still benefitted from ICB. A more comprehensive multivariate analysis including cancer type, specific gene mutations, and TMB revealed that ICB treatment was an independent predictor of improved overall survival. Therefore, ICB-based therapeutic trials are beneficial in patients with advanced solid malignancies, but the most benefit may be restricted to patients with the right combination of TMB and specific tumor histology and genotype.

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1-3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10-18.

Everolimus, Letrozole, and Metformin in Women with Advanced or Recurrent Endometrioid Endometrial Cancer: A Multi-Center, Single Arm, Phase II Study

PURPOSE

Treatment for patients with recurrent endometrioid endometrial cancer (EEC) are limited as paclitaxel is the only second-line chemotherapy with a response rate >13%. Targeting PIK3/mTOR in combination with hormonal therapy has shown promise. The addition of metformin may enhance this response. We conducted a phase II study evaluating everolimus, letrozole, and metformin in advanced/recurrent EEC.

PATIENTS AND METHODS

A Simon two-stage design was employed. Women with ≤2 prior chemotherapy regimens for recurrence were eligible. Pretreatment biopsy was required, followed by everolimus 10 mg orally, letrozole 2.5 mg orally, and metformin 500 mg orally twice a day on a 4-week cycle. The primary endpoint was clinical benefit (CB), defined as complete response (CR), partial response (PR), or stable disease (SD) confirmed at 16 weeks. Patients were treated until progression or toxicity.

RESULTS

Sixty-two patients were enrolled. Median age was 62 years (40-77) with 401 cycles completed, median of 6 cycles (1-31). Fifty-four patients were evaluable for response with a CB rate of 50% (27/54). Best overall response (OR) was PR 28% (15/54) and SD 22% (12/54). Thirteen patients received >12 cycles. Median follow-up was 17.9 months (2-47). Median progression-free survival was 5.7 [95% confidence interval (CI), 3.0-8.1] and OS was 19.6 months (95% CI, 14.2-26.3). Positive progesterone receptor expression was associated with CB (89.5% vs. 27.3%, P = 0.001).

CONCLUSIONS

Everolimus, letrozole, and metformin resulted in 50% CB and 28% OR in women with recurrent EEC. Progesterone receptor-positive tumors may have better response; validation studies are needed.See related commentary by Madariaga et al., p. 523.

Long-term overall survival and prognostic score predicting survival: the IMPACT study in precision medicine

Background

In 2007, we initiated IMPACT, a precision medicine program for patients referred for participation in early-phase clinical trials. We assessed the correlation of factors, including genomically matched therapy, with overall survival (OS).

Patients and methods

We performed molecular profiling (Clinical Laboratory Improvement Amendments) (genes ≤ 182) for patients with lethal/refractory advanced cancers referred to the Phase 1 Clinical Trials Program. Matched therapy, if available, was selected on the basis of genomics. Clinical trials varied over time and included investigational drugs against various targets (single agents or combinations). Patients were followed up for up to 10 years.

Results

Of 3487 patients who underwent tumor molecular profiling, 1307 (37.5%) had ≥ 1 alteration and received therapy (matched, 711; unmatched, 596; median age, 57 years; 39% men). Most common tumors were gastrointestinal, gynecologic, breast, melanoma, and lung. Objective response rates were: matched 16.4%, unmatched 5.4% (p < .0001); objective response plus stable disease ≥ 6 months rates were: matched 35.3% and unmatched 20.3%, (p < .001). Respective median progression-free survival: 4.0 and 2.8 months (p < .0001); OS, 9.3 and 7.3 months; 3-year, 15% versus 7%; 10-year, 6% vs. 1% (p < .0001). Independent factors associated with shorter OS (multivariate analysis) were performance status > 1 (p < .001), liver metastases (p < .001), lactate dehydrogenase levels > upper limit of normal (p < .001), PI3K/AKT/mTOR pathway alterations (p < .001), and non-matched therapy (p < .001). The five independent factors predicting shorter OS were used to design a prognostic score.

Conclusions

Matched targeted therapy was an independent factor predicting longer OS. A score to predict an individual patient’s risk of death is proposed.

Trial registration

ClinicalTrials.gov, NCT00851032, date of registration February 25, 2009.

Phase II, 2-stage, 2-arm, PIK3CA mutation stratified trial of MK-2206 in recurrent endometrial cancer

Endometrial cancers have high rates of phosphoinositide 3-kinase (PI3K) pathway alterations. MK-2206 is an allosteric inhibitor of AKT, an effector kinase of PI3K signals. We hypothesized patients with tumors harboring PIK3CA mutations would be more likely to benefit from MK-2206 than those without PIK3CA mutation. A Phase II study was performed in patients with recurrent endometrial cancer; all histologies except carcinosarcoma were eligible. Up to two prior chemotherapy lines were permitted, excluding prior treatment with PI3K pathway inhibitors. The first 18 patients were treated with MK-2206 200 mg weekly. Due to unacceptable toxicity, dose was reduced to 135 mg. Co-primary endpoints were objective response rate (ORR) and progression-free survival at 6 months (6moPFS). Thirty-seven patients were enrolled (one ineligible). By somatic PIK3CA mutation analysis, nine patients were mutant (MT) [one with partial response (PR)/6moPFS, two with 6moPFS]. Twenty-seven patients were wild-type (WT) (one PR and four 6moPFS). Most common toxicities were rash (44%), fatigue (41%), nausea (42%) and hyperglycemia (31%). Grade 3 and 4 toxicities occurred in 25 and 17% of patients, respectively. Exploratory analysis found serous histology had greater 6moPFS as compared to all other histologies (5/8 vs. 2/28, p = 0.003). PTEN expression was associated with median time to progression (p = 0.04). No other significant associations with PI3K pathway alterations were identified. There is limited single agent activity of MK-2206 in PIK3CA MT and PIK3CA WT endometrial cancer populations. Activity was detected in patients with serous histology and due to their poor outcomes warrants further study (NCT01307631).

G-protein coupled receptor 64 (GPR64) acts as a tumor suppressor in endometrial cancer

BACKGROUND

Endometrial cancer is the most common gynecological cancer. G-protein coupled receptor 64 (GPR64) belongs to a family of adhesion GPCRs and plays an important role in male fertility. However, the function of GPR64 has not been studied in endometrial cancer. Our objective is to investigate the role of GPR64 in endometrial cancer.

METHODS

We examined the levels of GPR64 in human endometrioid endometrial carcinoma by immunohistochemistry analysis. To determine a tumor suppressor role of GPR64 in endometrial cancer, we used a siRNA loss of function approach in human endometrial adenocarcinoma cell lines.

RESULTS

GPR64 levels were remarkably lower in 10 of 21 (47.62%) of endometrial carcinoma samples compared to control. Depletion of GPR64 by siRNA transfection revealed an increase of colony formation ability, cell proliferation, cell migration, and invasion activity in Ishikawa and HEC1A cells. The expression of Connexin 43 (Cx43), a member of the large family of gap junction proteins, was reduced through activation of AMP-activated protein kinase (AMPK) in Ishikawa cells with GPR64-deficicy.

CONCLUSIONS

These results suggest that GPR64 plays an important tumor suppressor role in endometrial cancer.

Abstract 3162: Prognostic value of tumor mutational burden using a 409 gene NGS panel in cancer patients with advanced stage recurrent or treatment refractory disease

Tumor Mutational Burden (TMB) is a promising biomarker for prediction of response to immune checkpoint blockade (ICB). It is uncertain whether ICB has prognostic value outside of ICB therapy. The CMS400 next generation sequencing panel (NGS) is a 409 gene, 15,992 amplicon, and 1.745 Mb panel instituted during 2014-2015 and run for 556 cancer patients who had been consented for participation within a prospective molecular pathology biomarker trial (PA14-0099). All patients had advanced or recurrent solid tumor malignancies that were refractory to at least one line of systemic therapy prior to enrollment. Survival time was calculated from time of NGS-tested tissue collection. TMB was calculated by dividing reported mutations (RM) by 1.745Mb, the genetic footprint of the NGS panel. Subtraction of germline single nucleotide polymorphisms was performed for each patient. GraphPad Prism 7.03 software was used to calculate p values and to plot Kaplan-Meier survival curves. One hundred seven patients (19.2%) received ICB. When stratified by reported mutations (RM: 0, 1, 2, 3, 4-5, 6-7, 8-9, 10-18, and &gt;19), a statistically significant decrement of overall survival was seen with increasing TMB in patients not treated with ICB (Table 1, p&lt;0.0001). Also, in patients treated with ICB, significantly increased overall survival was seen on the extreme ends of the TMB spectrum (Table 1, p=0.0249). In contrast, stratification by the top four histologic diagnoses (Colorectal ADCA [n=94] - 34.2 months, breast ductal ADCA [n=44] - 26.6 months, gynecologic high grade serous [n=39] - 45.6 months, and lung ADCA [n=30] - 31.5 months) did not show difference in overall survival (p=0.332). We report here a novel molecular phenomena showing that high TMB in patients with advanced cancers is associated with worse survival. This negative impact of high TMB can be reversed by treatment with ICB. These effects of ICB were seen across a broad spectrum of cancer types.

Median Survival Stratified by Tumor Mutational Burden and ICB Treatment StatusAll PtsAll PtsICB TreatedICB TreatedNo ICBNo ICBReported Mutations# of PtsMedian Survival (Months)# of PtsMedian Survival (Months)# of PtsMedian Survival (Months)p-value (Log-rank)Hazard Ratio of ICB Therapy95% CI of HR of ICB Therapy0 RM7150.71958.85248.50.3190.7050.368 - 1.341 RM8550.91262.07347.40.3390.6840.345 - 1.362 RM9433.91928.07533.90.8650.9510.535 - 1.693 RM8830.51951.26928.90.1890.7040.428 - 1.164-5 RM9330.81141.08230.40.5390.8150.442 - 1.506-7 RM4928.41127.33828.550.6230.8270.401 - 1.718-18 RM5623.95828.84823.10.5491.2520.553 - 2.84&gt;19 RM2041.38102.31224.20.00230.1800.0599 - 0.543Total55635.810747.944933.40.00490.7070.567 - 0.882p-value (Log-rank)&lt;0.00010.0249&lt;0.0001

Citation Format: Richard K. Yang, Peng Wang, Fatima Z. Jelloul, Mark J. Routbort, Scott Kopetz, Kenna R. Shaw, Jack J. Lee, Jiexin Zhang, Hui Chen, Keyur P. Patel, Raja Luthra, Russell R. Broaddus. Prognostic value of tumor mutational burden using a 409 gene NGS panel in cancer patients with advanced stage recurrent or treatment refractory disease [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 3162.

Microsatellite Instability Occurs in a Subset of Follicular Thyroid Cancers

BACKGROUND

Inactivation of DNA mismatch repair (MMR) and the resulting microsatellite instability (MSI) are frequently observed in endometrial, stomach, and colorectal cancers, as well as more rarely in other solid tumor types. The prevalence of MSI in thyroid cancer has not been explored in depth, although recent studies utilizing data from large cancer sequencing efforts such as The Cancer Genome Atlas indicate that MSI is absent or at least very rare in the most common and most well studied histologic subtype, papillary thyroid carcinoma. This study aimed to determine the prevalence of MSI in thyroid cancer by using a large series comprising all major histological subtypes.

METHODS

A total of 485 thyroid cancer patients were screened for MSI/MMR deficiency, including all major histologic subtypes (195 papillary thyroid carcinoma, 156 follicular thyroid carcinoma [FTC], 50 anaplastic thyroid carcinoma, 65 medullary thyroid carcinoma, and 17 poorly differentiated thyroid carcinomas) by using a combination of polymerase chain reaction-based detection, immunohistochemistry, and next-generation sequencing.

RESULTS

A total of four tumors were MSI-high and had loss of MMR protein expression, all of which were from FTC patients. Whole-exome sequencing was performed on two MSI-high FTCs and revealed a hemizygous loss of function mutation in MSH2 in one tumor.

CONCLUSIONS

Based on these data, it is estimated that the overall prevalence of MSI in FTC is 2.5%, and MSI is either entirely absent or rare in other histology subtypes of thyroid carcinoma. These findings highlight the importance of testing for MSI in FTC.

Use of a Targeted Exome Next-Generation Sequencing Panel Offers Therapeutic Opportunity and Clinical Benefit in a Subset of Patients With Advanced Cancers

PURPOSE

Smaller hotspot-based next-generation sequencing (NGS) panels have emerged to support standard of care therapy for patients with cancer. When standard treatments fail, it is unknown whether additional testing using an expanded panel of genes provides any benefit. The purpose of this study was to determine if larger sequencing panels that capture additional actionable genes, coupled with decision support, translates into treatment with matched therapy after frontline therapy has failed.

PATIENTS AND METHODS

A prospective protocol accrued 521 patients with a wide variety of refractory cancers. NGS testing using a 46- or 50-gene hotspot assay, then a 409-gene whole-exome assay, was sequentially performed in a Clinical Laboratory Improvement Amendments–certified clinical laboratory. A decision-support team annotated somatic alterations in clinically actionable genes for function and facilitated therapeutic matching. Survival and the impact of matched therapy use were determined by Kaplan-Meier estimate, log-rank test, and Cox proportional hazards regression.

RESULTS

The larger NGS panel identified at least one alteration in an actionable gene not previously identified in the smaller sequencing panel in 214 (41%) of 521 of enrolled patients. After the application of decision support, 41% of the alterations in actionable genes were considered to affect the function of the gene and were deemed actionable. Forty patients (40 of 214 [19%]) were subsequently treated with matched therapy. Treatment with matched therapy was associated with significantly improved overall survival compared with treatment with nonmatched therapy (P = .017).

CONCLUSION

Combining decision support with larger NGS panels that incorporate genes beyond those recommended in current treatment guidelines helped to identify patients who were eligible for matched therapy while improving overall treatment selection and survival. This survival benefit was restricted to a small subset of patients.

Pleiotropic Effects of PPARD Accelerate Colorectal Tumorigenesis, Progression, and Invasion

APC mutations activate aberrant β-catenin signaling to drive initiation of colorectal cancer; however, colorectal cancer progression requires additional molecular mechanisms. PPAR-delta (PPARD), a downstream target of β-catenin, is upregulated in colorectal cancer. However, promotion of intestinal tumorigenesis following deletion of PPARD in Apc^min mice has raised questions about the effects of PPARD on aberrant β-catenin activation and colorectal cancer. In this study, we used mouse models of PPARD overexpression or deletion combined with APC mutation (Apc^Δ580 ) in intestinal epithelial cells (IEC) to elucidate the contributions of PPARD in colorectal cancer. Overexpression or deletion of PPARD in IEC augmented or suppressed β-catenin activation via up- or downregulation of BMP7/TAK1 signaling and strongly promoted or suppressed colorectal cancer, respectively. Depletion of PPARD in human colorectal cancer organoid cells inhibited BMP7/β-catenin signaling and suppressed organoid self-renewal. Treatment with PPARD agonist GW501516 enhanced colorectal cancer tumorigenesis in Apc^Δ580 mice, whereas treatment with PPARD antagonist GSK3787 suppressed tumorigenesis. PPARD expression was significantly higher in human colorectal cancer-invasive fronts versus their paired tumor centers and adenomas. Reverse-phase protein microarray and validation studies identified PPARD-mediated upregulation of other proinvasive pathways: connexin 43, PDGFRβ, AKT1, EIF4G1, and CDK1. Our data demonstrate that PPARD strongly potentiates multiple tumorigenic pathways to promote colorectal cancer progression and invasiveness. SIGNIFICANCE: These findings address long-standing, important, and unresolved questions related to the potential role of PPARD in APC mutation-dependent colorectal tumorigenesis by showing PPARD activation enhances APC mutation-dependent tumorigenesis.

Prospective Randomized Biomarker Study of Metformin and Lifestyle Intervention for Prevention in Obese Women at Increased Risk for Endometrial Cancer

Obesity increases risk of endometrial cancer through dysregulation of estrogen and insulin signaling. The primary aim of this study was to evaluate the impact of metformin or lifestyle intervention on endometrial proliferation in postmenopausal obese women. Secondary aims included evaluating obesity-related biomarkers and adverse events experienced. Obese, postmenopausal women with prediabetes were randomized into four groups for a 16-week intervention using a 2 (metformin 1700 mg/day vs. placebo) × 2 (lifestyle intervention vs. no lifestyle intervention) factorial design. Pre- and postintervention endometrial proliferation, anthropometrics, body composition, and serum biomarkers (sex hormones, sex hormone binding globulin, IGF-I, adiponectin, omentin, insulin, glucose, and others) were assessed. Data were analyzed with linear regression models and false-discovery rate correction. Of 576 women approached for the study, 52 attended initial screening, 29 were eligible and randomized, and 26 completed the study. Lifestyle intervention resulted in significant loss of weight (-4.23 kg, P = 0.006) and total fat mass (-3.23 kg, P < 0.001). Participants receiving metformin lost 3.43 kg of weight (P = 0.023), but this was not statistically significant after multiple comparisons adjustment controlling false-discovery rate to 10%. Endometrial proliferation was low at baseline (mean 7.1%) and remained unchanged by 16 weeks, but included substantial variability. Metformin and lifestyle intervention produced minor changes to serum biomarkers. Lifestyle intervention produced the most significant changes in weight and body composition. While it is known that obese postmenopausal women are at increased risk for endometrial cancer, improved biomarkers are needed to stratify risk and test prevention strategies, particularly at the endometrial tissue level. Cancer Prev Res; 11(8); 477-90. ©2018 AACR.

Abstract 5501: The role of G-protein coupled receptor 64 (GPR64) as a tumor suppressor in endometrial cancer

Endometrial cancer is the most common gynecologic cancer. G-protein coupled receptor 64 (GPR64) belongs to a family of adhesion GPCRs and plays an important role for male fertility. However, GPR64 function has not been reported in endometrial cancer. Our objective is to investigate the role of GPR64 in endometrial cancer. We examined the levels of GPR64 in human endometrial cancer tissue by immunohistochemistry analysis. GPR64 levels were significantly lower in 10 of 21 (47.62%) of endometrial carcinoma samples compared to control. To test whether GPR64 has a role of tumor suppressor in endometrial cancer, we used an siRNA loss-of-function approach in human endometrial adenocarcinoma cell lines. Depletion of GPR64 by siRNA transfection in Ishikawa and HEC1A cells showed an increase of colony formation ability and cell proliferation. Depletion of GPR64 also significantly increased the migration and invasion activity of Ishikawa and HEC1A cells. Furthermore, the phosphorylation of AMP-activated protein kinase (AMPK) and expression of Connexin 43 (Cx43), a member of the large family of gap junction proteins, were regulated in GPR64-deficient Ishikawa cells. These results suggest that GPR64 plays an important role for cell proliferation, migration, and invasion as a tumor suppressor in endometrial cancer.

Citation Format: Jung-Yoon Yoo, Jong Il Ahn, Tae Hoon Kim, Russell R. Broaddus, Jeong Mook Lim, Ho-Geun Yoon, Jae-Wook Jeong. The role of G-protein coupled receptor 64 (GPR64) as a tumor suppressor in endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5501.

MIG-6 suppresses endometrial epithelial cell proliferation by inhibiting phospho-AKT

Background

Aberrant hyperactivation of epithelial proliferation, AKT signaling, and association with unopposed estrogen (E2) exposure is the most common endometrial cancer dysfunction. In the normal uterus, progesterone (P4) inhibits proliferation by coordinating stromal-epithelial cross-talk, which we previously showed is mediated by the function of Mitogen-inducible gene 6 (Mig-6). Despite their attractive characteristics, non-surgical conservative therapies based on progesterone alone have not been universally successful. One barrier to this success has been the lack of understanding of the P4 effect on endometrial cells.

Method

To further understand the role of Mig-6 and P4 in controlling uterine proliferation, we developed a Sprr2f-cre driven mouse model where Mig-6 is specifically ablated only in the epithelial cells of the uterus (Sprr2f^cre+Mig-6^f/f). We examined P4 effect and regulation of AKT signaling in the endometrium of mutant mice.

Results

Sprr2f^cre+Mig-6^f/f mice developed endometrial hyperplasia. P4 treatment abated the development of endometrial hyperplasia and restored morphological and histological characteristics of the uterus. P4 treatment reduced cell proliferation which was accompanied by decreased AKT signaling and the restoration of stromal PGR and ESR1 expression. Furthermore, our in vitro studies revealed an inhibitory effect of MIG-6 on AKT phosphorylation as well as MIG-6 and AKT protein interactions.

Conclusions

These data suggest that endometrial epithelial cell proliferation is regulated by P4 mediated Mig-6 inhibition of AKT phosphorylation, uncovering new mechanisms of P4 action. This information may help guide more effective non-surgical interventions in the future.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4502-7) contains supplementary material, which is available to authorized users.

Molecular Profile of Advanced Thyroid Carcinomas by Next-Generation Sequencing: Characterizing Tumors Beyond Diagnosis for Targeted Therapy

Next-generation sequencing (NGS) for molecular diagnostics allows simultaneous testing of activating oncogenes and tumor suppressor mutations in multiple signal pathways. Extended mutational profiling of advanced thyroid cancers may enhance considerations for targeted therapies. We analyzed clinically derived molecular profiling of 216 patients with advanced thyroid carcinoma using NGS (Ion Torrent Personal Genome Machine) from April 2012 to February 2014. We examined substitutions and small indels in 46 or 50 cancer-related genes using Ampliseq Cancer Hotspot panel in respect to tumor diagnosis and clinical correlations.Mutations were common in advanced thyroid carcinomas 154 (71%) predominately in targetable MAPK pathway (146/216, 68%), and several PI3K/AKT pathway (8, 4%; six as comutations). BRAF V600E mutation associated with papillary (94/139, 68%), poorly differentiated (4/39, 10%), and anaplastic (3/12, 25%) carcinomas. NRAS mutations occurred in follicular (5/12, 42%) and poorly differentiated thyroid carcinoma (12/39, 31%). Tumor suppressor mutations (16, 7%) occurred predominantly in TP53 in Hurthle cell (2/5, 40%, the only mutation), in anaplastic (3/12, 25%) and poorly differentiated thyroid carcinoma (4/39, 10%) some as comutations and in papillary thyroid carcinoma (5/139, 4%) always a comutation. Kaplan-Meier analysis of patients with poorly differentiated thyroid carcinoma containing activating mutations who received targeted therapeutics showed improved survival compared to similarly treated patients without mutations in targetable pathways (P = 0.02). In conclusion, MAPK pathway is the predominant target for therapy in advance thyroid carcinomas; adding NGS enables the identification of comutations associated with resistance (PI3K/AKT). Within poorly differentiated thyroid carcinoma, the molecular profile may hold prognostic value in the era of targeted therapy. Mol Cancer Ther; 17(7); 1575-84. ©2018 AACR.

Predicting high-risk endometrioid carcinomas using proteins

Background

The lethality of endometrioid endometrial cancer (EEC) is primarily attributable to advanced-stage diseases. We sought to develop a biomarker model that predicts EEC surgical stage at the time of clinical diagnosis.

Results

PSES was significantly correlated with surgical stage in the TCGA cohort (P < 0.0001) and in the validation cohort (P = 0.0003). Even among grade 1 or 2 tumors, PSES was significantly higher in advanced than in early stage tumors in both the TCGA (P = 0.005) and MD Anderson Cancer Center (MDACC) (P = 0.006) cohorts. Patients with positive PSES score had significantly shorter progression-free survival than those with negative PSES in the TCGA (hazard ratio [HR], 2.033; 95% CI, 1.031 to 3.809; P = 0.04) and validation (HR, 3.306; 95% CI, 1.836 to 9.436; P = 0.0007) cohorts. The ErbB signaling pathway was most significantly enriched in the PSES proteins and downregulated in advanced stage tumors.

Methods

Using reverse-phase protein array expression profiles of 170 antibodies for 210 EEC cases from TCGA, we constructed a Protein Scoring of EEC Staging (PSES) scheme comprising 6 proteins (3 of them phosphorylated) for surgical stage prediction. We validated and evaluated its diagnostic potential in an independent cohort of 184 EEC cases obtained at MDACC using receiver operating characteristic curve analyses. Kaplan-Meier survival analysis was used to examine the association of PSES score with patient outcome, and Ingenuity pathway analysis was used to identify relevant signaling pathways. Two-sided statistical tests were used.

Conclusions

PSES may provide clinically useful prediction of high-risk tumors and offer new insights into tumor biology in EEC.

Treatment of Low-Risk Endometrial Cancer and Complex Atypical Hyperplasia With the Levonorgestrel-Releasing Intrauterine Device

OBJECTIVE

To assess efficacy of the levonorgestrel-releasing intrauterine device (LNG-IUD) for treatment of complex atypical hyperplasia or low-grade endometrial cancer.

METHODS

This retrospective case series included all patients treated with the LNG-IUD for complex atypical hyperplasia or early-grade endometrial cancer from January 2003 to June 2013. Response rates were calculated and the association of response with clinicopathologic factors, including age, body mass index, and uterine size, was determined.

RESULTS

Forty-six patients diagnosed with complex atypical hyperplasia or early-grade endometrial cancer were treated with the LNG-IUD. Of 32 evaluable patients at the 6-month time point, 15 had complex atypical hyperplasia (47%), nine had G1 endometrial cancer (28%), and eight had grade 2 endometrial cancer (25%). Overall response rate was 75% (95% CI 57-89) at 6 months; 80% (95% CI 52-96) in complex atypical hyperplasia, 67% (95% CI 30-93) in grade 1 endometrial cancer, and 75% (CI 35-97) in grade 2 endometrial cancer. Of the clinicopathologic features evaluated, there was a trend toward the association of lack of exogenous progesterone effect in the pathology specimen with nonresponse to the IUD (P=.05). Median uterine diameter was 1.3 cm larger in women who did not respond to the IUD (P=.04).

CONCLUSION

Levonorgestrel-releasing IUD therapy for the conservative treatment of complex atypical hyperplasia or early-grade endometrial cancer resulted in return to normal histology in a majority of patients.

Detection of somatic mutations in cell-free DNA in plasma and correlation with overall survival in patients with solid tumors

A suitable clinical-grade platform is required for detection of somatic mutations with high sensitivity in cell-free DNA (cfDNA) of patients with solid tumors. In this study, we evaluated in parallel ultra-deep NGS with MassARRAY and allele-specific droplet digital PCR (ddPCR) for cfDNA genotyping and correlated cfDNA yield and mutation status with overall survival (OS) of patients. We assessed plasma samples from 46 patients with various advanced metastatic solid tumors and known mutations by deep sequencing using an Ampliseq cancer hotspot panel V2 on Ion Proton. A subset of these samples with DNA availability was tested by ddPCR and UltraSEEK MassARRAY for mutation detection in 5 genes (IDH1, PIK3CA, KRAS, BRAF, and NRAS). Sixty one of 104 expected tissue mutations and 6 additional mutations not present in the tissue were detected in cfDNA. ddPCR and MassARRAY showed 83% and 77% concordance with NGS for mutation detection with 100% and 79% sensitivity, respectively. The median OS of patients with lower cfDNA yield (74 vs 50 months; P < 0.03) and cfDNA negative for mutations (74.2 vs 53 months; p < 0.04) was significantly longer than in patients with higher cfDNA yield and positive for mutations. A limit-of-detection of 0.1% was demonstrated for ddPCR and MassARRAY platforms using a serially diluted positive cfDNA sample. The MassARRAY and ddPCR systems enable fast and cost-effective genotyping for a targeted set of mutations and can be used for single gene testing to guide response to chemotherapy or for orthogonal validation of NGS results.

Opposing effects of cancer-type-specific SPOP mutants on BET protein degradation and sensitivity to BET inhibitors

It is generally assumed that recurrent mutations within a given cancer driver gene elicit similar drug responses. Cancer genome studies have identified recurrent but divergent missense mutations in the substrate recognition domain of the ubiquitin ligase adaptor SPOP in endometrial and prostate cancer. Their therapeutic implications remain incompletely understood. Here, we analyzed changes in the ubiquitin landscape induced by endometrial cancer-associated SPOP mutations and identified BRD2, BRD3 and BRD4 proteins (BETs) as SPOP-CUL3 substrates that are preferentially degraded by endometrial SPOP mutants. The resulting reduction of BET protein levels sensitized cancer cells to BET inhibitors. Conversely, prostate cancer-specific SPOP mutants impaired degradation of BETs, promoting resistance against their pharmacologic inhibition. These results uncover an oncogenomics paradox, whereby mutations within the same domain evoke opposing drug susceptibilities. Specifically, we provide a molecular rationale for the use of BET inhibitors to treat endometrial but not prostate cancer patients with SPOP mutations.

Universal Point of Care Testing for Lynch Syndrome in Patients with Upper Tract Urothelial Carcinoma

PURPOSE

Patients with Lynch syndrome are at risk for upper tract urothelial carcinoma. We sought to identify the incidence and most reliable means of point of care screening for Lynch syndrome in patients with upper tract urothelial carcinoma.

MATERIALS AND METHODS

A total of 115 consecutive patients with upper tract urothelial carcinoma without a history of Lynch syndrome were universally screened during followup from January 2013 through July 2016. We evaluated patient and family history using AMS (Amsterdam criteria) I and II, and tumor immunohistochemistry for mismatch repair proteins and microsatellite instability. Patients who were positive for AMS I/II, microsatellite instability or immunohistochemistry were classified as potentially having Lynch syndrome and referred for clinical genetic analysis and counseling. Patients with known Lynch syndrome served as positive controls.

RESULTS

Of the 115 patients 16 (13.9%) screened positive for potential Lynch syndrome. Of these patients 7.0% met AMS II criteria, 11.3% had loss of at least 1 mismatch repair protein and 6.0% had high microsatellite instability. All 16 patients were referred for germline testing, 9 completed genetic analysis and counseling, and 6 were confirmed to have Lynch syndrome. All 7 patients with upper tract urothelial carcinoma who had a known history of Lynch syndrome were positive for AMS II criteria and at least a single mismatch repair protein loss while 5 of 6 had high microsatellite instability.

CONCLUSIONS

We identified 13.9% of upper tract urothelial carcinoma cases as potential Lynch syndrome and 5.2% as confirmed Lynch syndrome at the point of care. These findings have important implications for universal screening of upper tract urothelial carcinoma, representing one of the highest rates of undiagnosed genetic disease in a urological cancer.

CTNNB1 (beta-catenin) mutation identifies low grade, early stage endometrial cancer patients at increased risk of recurrence

Although the majority of low grade, early stage endometrial cancer patients will have good survival outcomes with surgery alone, those patients who do recur tend to do poorly. Optimal identification of the subset of patients who are at high risk of recurrence and would benefit from adjuvant treatment has been difficult. The purpose of this study was to evaluate the impact of somatic tumor mutation on survival outcomes in this patient population. For this study, low grade was defined as endometrioid FIGO grades 1 or 2, while early stage was defined as endometrioid stages I or II (disease confined to the uterus). Next-generation sequencing was performed using panels comprised of 46-200 genes. Recurrence-free and overall survival was compared across gene mutational status in both univariate and multivariate analyses. In all, 342 patients were identified, 245 of which had endometrioid histology. For grades 1-2, stages I-II endometrioid endometrial cancer patients, age (HR 1.07, 95% CI 1.03-1.10), CTNNB1 mutation (HR 5.97, 95% CI 2.69-13.21), and TP53 mutation (HR 4.07, 95% CI 1.57-10.54) were associated with worse recurrence-free survival on multivariate analysis. When considering endometrioid tumors of all grades and stages, CTNNB1 mutant tumors were associated with significantly higher rates of grades 1-2 disease, lower rates of deep myometrial invasion, and lower rates of lymphatic/vascular space invasion. When both TP53 and CTNNB1 mutations were considered, presence of either TP53 mutation or CTNNB1 mutation remained a statistically significant predictor of recurrence-free survival on multivariate analysis and was associated with a more precise confidence interval (HR 4.69, 95% CI 2.38-9.24). Thus, mutational analysis of a 2 gene panel of CTNNB1 and TP53 can help to identify a subset of low grade, early stage endometrial cancer patients who are at high risk of recurrence.