Characterization of mismatch-repair/microsatellite instability-discordant endometrial cancers.

BACKGROUND: Mismatch-repair (MMR)/microsatellite instability (MSI) status has therapeutic implications in endometrial cancer (EC). The authors evaluated the concordance of testing and factors contributing to MMR expression heterogeneity. METHODS: Six hundred sixty-six ECs were characterized using immunohistochemistry (IHC), MSI testing, and mut-L homolog 1 (MLH1) methylation. Select samples underwent whole-transcriptome analysis and next-generation sequencing. MMR expression of metastatic/recurrent sites was evaluated. RESULTS: MSI testing identified 27.3% of cases as MSI-high (n = 182), MMR IHC identified 25.1% cases as MMR-deficient (n = 167), and 3.8% of cases (n = 25) demonstrated discordant results. A review of IHC staining explained discordant results in 18 cases, revealing subclonal loss of MLH1/Pms 1 homolog 2 (PMS2) (n = 10) and heterogeneous MMR IHC (mut-S homolog 6 [MSH6], n = 7; MLH1/PMS2, n = 1). MSH6-associated Lynch syndrome was diagnosed in three of six cases with heterogeneous expression. Subclonal or heterogeneous cases had a 38.9% recurrence rate (compared with 16.7% in complete MMR-deficient cases and 9% in MMR-proficient cases) and had abnormal MMR IHC results in all metastatic recurrent sites (n = 7). Tumors with subclonal MLH1/PMS2 demonstrated 74 differentially expressed genes (determined using digital spatial transcriptomics) when stratified by MLH1 expression, including many associated with epithelial-mesenchymal transition. CONCLUSIONS: Subclonal/heterogeneous MMR IHC cases showed epigenetic loss in 66.7%, germline mutations in 16.7%, and somatic mutations in 16.7%. MMR IHC reported as intact/deficient missed 21% of cases of Lynch syndrome. EC with subclonal/heterogeneous MMR expression demonstrated a high recurrence rate, and metastatic/recurrent sites were MMR-deficient. Transcriptional analysis indicated an increased risk for migration/metastasis, suggesting that clonal MMR deficiency may be a driver for tumor aggressiveness. Reporting MMR IHC only as intact/deficient, without reporting subclonal and heterogeneous staining, misses opportunities for biomarker-directed therapy. PLAIN LANGUAGE SUMMARY: Endometrial cancer is the most common gynecologic cancer, and 20%-40% of tumors have a defect in DNA proofreading known as mismatch-repair (MMR) deficiency. These results can be used to guide therapy. Tests for this defect can yield differing results, revealing heterogeneous (mixed) proofreading capabilities. Tumors with discordant testing results and mixed MMR findings can have germline or somatic defects in MMR genes. Cells with deficient DNA proofreading in tumors with mixed MMR findings have DNA expression profiles linked to more aggressive characteristics and cancer spread. These MMR-deficient cells may drive tumor behavior and the risk of spreading cancer.

Epigenetic MMR defect identifies a risk group not accounted for through traditional risk stratification algorithms in endometrial cancer.

Purpose: We sought to evaluate the contribution of mismatch repair (MMR) status to traditional risk stratification algorithms used to predict nodal involvement and recurrence in a large single-institution cohort. Methods: Endometrioid endometrial cancer (EC) cases from 2014-2020 were evaluated. MMR immunohistochemistry (IHC) was performed universally. Uterine factors assessed in the Mayo criteria were used to retrospectively classify patients as low or high risk for lymphatic spread. Patients were classified according to risk for recurrence using GOG 99 and PORTEC criteria. Associations were evaluated using chi-square and t-tests and contributing factors assessed using logistic regression models. Results: 1,514 endometrioid EC were evaluated; 392 (25.9%) were MMR (MMR) deficient of which 80.4% of MMR defects were associated with epigenetic silencing of MLH1. Epigenetic MMR defects were significantly more likely to be high risk for lymph node (LN) metastasis based on Mayo criteria (74.9% vs 60.6%, p=<0.001) and with the presence of LN metastasis (20.3 vs 10.5%, p=0.003) compared to MMR proficient tumors. Tumors with epigenetic MMR defects were significantly more likely to be classified as high or high intermediate risk using GOG99 and PORTEC criteria. Furthermore, cases with epigenetic MMR defects classified as low or low intermediate risk were significantly more likely to recur (GOG99 p=0.013; PORTEC p=0.008) and independently associated with worse disease-free survival (DFS). MMR status was found to be independently associated with worse DFS (HR 1.90; 95% CI 1.34-2.70; p=0.003) but not overall survival. Conclusion: While MMR deficient EC has been associated with poor prognostic features in prior reports; we demonstrate that only epigenetic MMR defects have poorer outcomes. Epigenetic MMR defect were independently associated with lymph node metastasis after controlling for risk criteria. Epigenetic MMR deficiency was found to be an independent predictor of recurrence beyond the factors considered in traditional risk stratification algorithms. Traditional uterine-based risk stratification algorithms may not fully reflect the risk for recurrence in MMR deficient tumors. Consideration should be given to implementing MMR status and MLH1 hypermethylation alongside traditional risk stratification algorithms. Performing MMR IHC on preoperative pathologic specimens may aid in risk stratification and patient counseling.

The contemporary presentation and diagnosis of endometrial cancer recurrence: When, where, and how?

OBJECTIVE: To examine patients with confirmed endometrial cancer recurrence; evaluate patterns, presentation, and mode of diagnosis. STUDY DESIGN: A retrospective review of women with endometrial cancer diagnosis between 2014 and 2020. Disease recurrences were evaluated. Medical records were reviewed focusing on presentation at time of recurrence. Relationships were assessed using χ2, Fisher's exact test, t-test, and Wilcoxon test. The Kaplan-Meier product limit was used to estimate survival. Multiple logistic regression analysis was used to assess the impact of covariates. RESULTS: Endometrial cancer recurrence was identified in 201 (11.7%) patients. Sixty percent (120/201) of patients presented with symptoms. Pain was the most common presenting symptom (23.4%, 47/201) and bleeding was reported in <14% (28/201). Patients with symptomatic presentation were less likely to be able to receive treatment for their recurrent disease (76.7% vs 91.3%, p = 0.005). Asymptomatic pelvic exam diagnosed recurrence in 13.4% (27/201) and was more common in patients initially diagnosed with early-stage disease (66.7% vs 34.5% p = 0.001) of endometrioid histology (66.7% vs 36.8%, p = 0.003) without prior adjuvant therapy (48.2% vs 17.9%, p = 0.001). More than1/3 of diagnoses were made by providers outside of the oncologic care team. CONCLUSION: The majority of women with recurrent endometrial cancer were symptomatic and pain is a common complaint associated with disease recurrence. Patients with symptomatic presentation of disease recurrence were less likely to receive treatment for recurrent disease but this did not result in an overall survival (OS) difference. Given the rising mortality rate of endometrial cancer further work is needed to develop multidisciplinary surveillance strategies that will enable meaningful treatment of disease recurrence.

Implementing universal upfront multi-gene panel testing in endometrial cancer: From cost to practical considerations.

OBJECTIVES: The routine use of upfront universal germline genetic testing among patients with newly diagnosed endometrial cancer (EC) has been proposed to improve diagnosis of Lynch syndrome (LS) and discover pathogenic variants (PVs) in other cancer susceptibility genes. We propose an algorithm prioritizing upfront multi-gene panel testing (MGPT) for newly diagnosed EC patients. METHODS: A decision analysis compared the cost of the current algorithm of universal mismatch repair (MMR) immunohistochemistry (IHC) for all EC cases to a new MGPT algorithm that employs upfront MGPT for all EC cases and reserves MMR IHC for the recurrent setting. The increase in the number of LS diagnoses using upfront MGPT, and the number of patients with PVs in BRCA1 and BRCA2 are also estimated. RESULTS: The MGPT algorithm demonstrated a cost savings of $259 per patient. Assuming 66,950 new cases of EC per year, this would represent $17.1 M of cost savings per year. When applied to all new diagnoses of EC in one year, the MGPT algorithm identified 660 (1%) additional cases of LS that would have been missed with the current algorithm. An additional 660 (1%) EC patients with BRCA1 or BRCA2 PVs would be diagnosed only through implementation of universal MGPT. CONCLUSIONS: The use of universal upfront MGPT is a practical consideration for patients with newly diagnosed EC for cost savings and improved diagnosis of highly penetrant cancer syndromes. Incorporation of germline genetic testing in the upfront setting represents an opportunity to improve access to genetic counseling and testing, and ultimately an avenue to achieve equity and improve the lives of our patients with EC and their families.

Endometrial Cancer: Who Lives, Who Dies, Can We Improve Their Story?

BACKGROUND: Endometrial cancer (EC) is the most common gynecologic cancer in the U.S. The objective of this cohort study was to characterize the clinical and pathologic features that are associated with endometrial cancer-specific death for women cared for at a single National Cancer Institute-designated comprehensive cancer center. PATIENTS, MATERIALS, AND METHODS: This is a retrospective cohort from 2014 to 2017 including all women who had a hysterectomy for EC. Charts were reviewed for clinical and pathologic data, focusing on survival outcomes. RESULTS: Seven hundred seventy-one patients with EC underwent hysterectomy with 760 informative for outcomes. Seventy-six (10%) deaths were related to their EC; 62 women died from recurrent EC. Nonendometrioid histology and advanced stage were predictors of recurrence and EC death. Among patients with endometrioid ECs, mismatch repair status was significantly associated with EC-specific survival (relative risk = 4.8; 95% confidence interval, 2.3-10.3; p < .0001). Most patients with EC who recurred died of their disease 62/83 (74.7%). Nearly half of the patients that recurred (27/62) had no additional therapy at the time of recurrence. Overall survival was significantly longer for those women who had additional treatment at the time of recurrence; however, the improvement in overall survival with therapy at recurrence was largely attributable to effects in those women who were adjuvant therapy naïve. CONCLUSION: Although there is benefit of treatment at the time of recurrence for treatment-naïve women; only approximately half of patients were able to receive therapy. There is an urgent need for continued efforts for more effective EC therapy in both the front-line and recurrent setting as well as early identification of cancer diagnosis and recurrence. IMPLICATIONS FOR PRACTICE: Approximately 10% of patients died of their endometrial cancer. Most deaths were from recurrent disease; however, almost 20% of endometrial cancer deaths were within 120 days of surgery. Although treatment at the time of recurrence improves overall survival, only approximately half of patients will receive therapy at the time of recurrence. Traditional prognostic features like histology and stage remain important to predict risk of recurrence, and newer biomarkers, such as mismatch repair status, may improve risk stratification and targeted therapy. There remains an urgent need for improved therapy and early detection of diagnosis and recurrence.

Prospective Statewide Study of Universal Screening for Hereditary Colorectal Cancer: The Ohio Colorectal Cancer Prevention Initiative.

Hereditary cancer syndromes infer high cancer risks and require intensive surveillance. Identification of high-risk individuals among patients with colorectal cancer (CRC) needs improvement. METHODS: Three thousand three hundred ten unselected adults who underwent surgical resection for primary invasive CRC were prospectively accrued from 51 hospitals across Ohio between January 1, 2013, and December 31, 2016. Universal Tumor screening (UTS) for mismatch repair (MMR) deficiency was performed for all, and pathogenic germline variants (PGVs) were identified using multigene panel testing (MGPT) in those who met at least one inclusion criterion: MMR deficiency, diagnosed < 50 years, multiple primary tumors (CRC or endometrial cancer), or with a first-degree relative with CRC or endometrial cancer. RESULTS: Five hundred twenty-five patients (15.9%) had MMR deficiency. Two hundred thirty-four of 3,310 (7.1%; 16% of the 1,462 who received MGPT) had 248 PGVs in cancer susceptibility genes. One hundred forty-two (4.3%) had a PGV in an MMR gene, and 101 (3.1%) had a PGV in a non-MMR gene. Ten with Lynch syndrome (LS) also had a non-MMR PGV and were included in both groups. Two (0.06%) had constitutional MLH1 hypermethylation. Of unexplained MMR-deficient patients, 88.4% (76 of 86) had double somatic MMR mutations. Testing for only MMR genes in MMR-deficient patients would have missed 18 non-MMR gene PGVs (7.3% of total PGVs identified). Had UTS been the only method used to screen for hereditary cancer syndromes, 38.6% (91 of 236) would have been missed, including 6.3% (9 of 144) of those with LS. These results have treatment implications as 5.3% (175 of 3,310) had PGVs in genes with therapeutic targets. CONCLUSION: UTS alone is insufficient for identifying a large proportion of CRC patients with hereditary syndromes, including some with LS. At a minimum, 7.1% of individuals with CRC have a PGV and pan-cancer MGPT should be considered for all patients with CRC.

Up-Front Multigene Panel Testing for Cancer Susceptibility in Patients With Newly Diagnosed Endometrial Cancer: A Multicenter Prospective Study.

PURPOSE: Clinical utility of up-front multigene panel testing (MGPT) is directly related to the frequency of pathogenic variants (PVs) in the population screened and how genetic findings can be used to guide treatment decision making and cancer prevention efforts. The benefit of MGPT for many common malignancies remains to be determined. In this study, we evaluated up-front MGPT in unselected patients with endometrial cancer (EC) to determine the frequency of PVs in cancer susceptibility genes. METHODS: Patients with EC were prospectively enrolled at nine Ohio institutions from October 1, 2017, to December 31, 2020. Nine hundred and sixty-one patients with newly diagnosed EC underwent clinical germline MGPT for 47 cancer susceptibility genes. In addition to estimating the prevalence of germline PVs, the number of individuals identified with Lynch syndrome (LS) was compared between MGPT and tumor-based screening. RESULTS: Likely pathogenic variants or PVs were identified in 97 of 961 women (10.1%). LS was diagnosed in 29 of 961 patients (3%; 95% CI, 2.1 to 4.3), with PVs in PMS2 most frequent. MGPT revealed nine patients with LS in addition to the 20 identified through routine tumor-based screening. BRCA1 and BRCA2 PVs were found in 1% (10 of 961; 95% CI, 0.6 to 1.9) of patients and that group was significantly enriched for type II ECs. CONCLUSION: This prospective, multicenter study revealed potentially actionable germline variants in 10% of unselected women with newly diagnosed EC, supporting the use of up-front MGPT for all EC patients. The discovery that BRCA1 or BRCA2 heterozygotes frequently had type II cancers points to therapeutic opportunities for women with aggressive histologic EC subtypes.

Evaluating the efficacy of enzalutamide and the development of resistance in a preclinical mouse model of type-I endometrial carcinoma.

Androgen Receptor (AR) signaling is a critical driver of hormone-dependent prostate cancer and has also been proposed to have biological activity in female hormone-dependent cancers, including type I endometrial carcinoma (EMC). In this study, we evaluated the preclinical efficacy of a third-generation AR antagonist, enzalutamide, in a genetic mouse model of EMC, Sprr2f-Cre;Ptenfl/fl. In this model, ablation of Pten in the uterine epithelium leads to localized and distant malignant disease as observed in human EMC. We hypothesized that administering enzalutamide through the diet would temporarily decrease the incidence of invasive and metastatic carcinoma, while prolonged administration would result in development of resistance and loss of efficacy. Short-term treatment with enzalutamide reduced overall tumor burden through increased apoptosis but failed to prevent progression of invasive and metastatic disease. These results suggest that AR signaling may have biphasic, oncogenic and tumor suppressive roles in EMC that are dependent on disease stage. Enzalutamide treatment increased Progesterone Receptor (PR) expression within both stromal and tumor cell compartments. Prolonged administration of enzalutamide decreased apoptosis, increased tumor burden and resulted in the clonal expansion of tumor cells expressing high levels of p53 protein, suggestive of acquired Trp53 mutations. In conclusion, we show that enzalutamide induces apoptosis in EMC but has limited efficacy overall as a single agent. Induction of PR, a negative regulator of endometrial proliferation, suggests that adding progestin therapy to enzalutamide administration may further decrease tumor burden and result in a prolonged response.

Germline and Somatic Tumor Testing in Epithelial Ovarian Cancer: ASCO Guideline.

PURPOSE: To provide recommendations on genetic and tumor testing for women diagnosed with epithelial ovarian cancer based on available evidence and expert consensus. METHODS: A literature search and prospectively defined study selection criteria sought systematic reviews, meta-analyses, randomized controlled trials (RCTs), and comparative observational studies published from 2007 through 2019. Guideline recommendations were based on the review of the evidence. RESULTS: The systematic review identified 19 eligible studies. The evidence consisted of systematic reviews of observational data, consensus guidelines, and RCTs. RECOMMENDATIONS: All women diagnosed with epithelial ovarian cancer should have germline genetic testing for BRCA1/2 and other ovarian cancer susceptibility genes. In women who do not carry a germline pathogenic or likely pathogenic BRCA1/2 variant, somatic tumor testing for BRCA1/2 pathogenic or likely pathogenic variants should be performed. Women with identified germline or somatic pathogenic or likely pathogenic variants in BRCA1/2 genes should be offered treatments that are US Food and Drug Administration (FDA) approved in the upfront and the recurrent setting. Women diagnosed with clear cell, endometrioid, or mucinous ovarian cancer should be offered somatic tumor testing for mismatch repair deficiency (dMMR). Women with identified dMMR should be offered FDA-approved treatment based on these results. Genetic evaluations should be conducted in conjunction with health care providers familiar with the diagnosis and management of hereditary cancer. First- or second-degree blood relatives of a patient with ovarian cancer with a known germline pathogenic cancer susceptibility gene variant should be offered individualized genetic risk evaluation, counseling, and genetic testing. Clinical decision making should not be made based on a variant of uncertain significance. Women with epithelial ovarian cancer should have testing at the time of diagnosis.

Rare BRIP1 Missense Alleles Confer Risk for Ovarian and Breast Cancer.

Germline loss-of-function mutations in BRCA1 interacting protein C-terminal helicase 1 (BRIP1) are associated with ovarian carcinoma and may also contribute to breast cancer risk, particularly among patients who develop disease at an early age. Normal BRIP1 activity is required for DNA interstrand cross-link (ICL) repair and is thus central to the maintenance of genome stability. Although pathogenic mutations have been identified in BRIP1, genetic testing more often reveals missense variants, for which the impact on molecular function and subsequent roles in cancer risk are uncertain. Next-generation sequencing of germline DNA in 2,160 early-onset breast cancer and 1,199 patients with ovarian cancer revealed nearly 2% of patients carry a very rare missense variant (minor allele frequency < 0.0001) in BRIP1. This is 3-fold higher than the frequency of all rare BRIP1 missense alleles reported in more than 60,000 individuals of the general population (P < 0.0001, χ 2 test). Using CRISPR-Cas9 gene editing technology and rescue assays, we functionally characterized 20 of these missense variants, focusing on the altered protein's ability to repair ICL damage. A total of 75% of the characterized variants rendered the protein hypomorph or null. In a clinical cohort of >117,000 patients with breast and ovarian cancer who underwent panel testing, the combined OR associated with BRIP1 hypomorph or null missense carriers compared with the general population was 2.30 (95% confidence interval, 1.60-3.30; P < 0.0001). These findings suggest that novel missense variants within the helicase domain of BRIP1 may confer risk for both breast and ovarian cancer and highlight the importance of functional testing for additional variants. SIGNIFICANCE: Functional characterization of rare variants of uncertain significance in BRIP1 revealed that 75% demonstrate loss-of-function activity, suggesting rare missense alleles in BRIP1 confer risk for both breast and ovarian cancer.

Dicer1 Phosphomimetic Promotes Tumor Progression and Dissemination.

Dicer1 functions as a tumor suppressor in mouse models. In humans, somatic mutations are associated with many cancers in adults, and patients with DICER1 syndrome with DICER1 germline mutations are susceptible to childhood cancers. Dicer is phosphorylated by the ERK-MAP kinase pathway and because this pathway is activated in human cancers, we asked whether phosphorylated Dicer1 contributed to tumor development. In human endometrioid cancers, we discovered that phosphorylated DICER1 is significantly associated with invasive disease. To test a direct involvement of Dicer1 phosphorylation in tumor development, we studied mice with phosphomimetic alterations at the two conserved serines phosphorylated by ERK and discovered that a phosphomimetic Dicer1 drives tumor development and dissemination in two independent murine cancer models (KRas+/LA1 and p53+/- ). Our findings demonstrate that phosphomimetic Dicer1 promotes tumor development and invasion. SIGNIFICANCE: This work highlights the relevance of Dicer1 phosphorylation in mammalian tumor development and dissemination.

GOG 8020/210: Risk stratification of lymph node metastasis, disease progression and survival using single nucleotide polymorphisms in endometrial cancer: An NRG oncology/gynecologic oncology group study.

OBJECTIVES: The ability to stratify a patient's risk of metastasis and survival permits more refined care. A proof of principle study was undertaken to investigate the relationship between single nucleotide polymorphisms (SNPs) in literature based candidate cancer genes and the risk of nodal metastasis and clinical outcome in endometrioid endometrial cancer (EEC) patients. METHODS: Surgically-staged EEC patients from the Gynecologic Oncology Group or Washington University School of Medicine with germline DNA available were eligible. Fifty-four genes represented by 384 SNPs, were evaluated by Illumina Custom GoldenGate array. Association with lymph node metastases was the primary outcome. Progression-free survival (PFS) and overall survival (OS) was also evaluated. RESULTS: 361 SNPs with high quality genotype data were evaluated in 337 patients with outcome data. Five SNPs in CXCR2 had an odds ratio (OR) between 0.68 and 0.70 (p-value ≤ 0.025). The A allele rs946486 in ABL had an OR of 1.5 (p-value = 0.01) for metastasis. The G allele in rs7795743 in EGFR had an OR for metastasis of 0.68 (p-value = 0.02) and hazard ratio (HR) for progression of 0.66 (p-value = 0.004). Importantly, no SNP met genome wide significance after adjusting for multiple test correcting and clinical covariates. The A allele in rs2159359 SNP in NME1 and the G allele in rs13222385 in EGFR were associated with worse OS. Both exhibited genome wide significance; rs13222385 remained significant after adjusting for prognostic clinical variables. CONCLUSION: SNPs in cancer genes including rs2159359 SNP in NME1 and rs13222385 in EGFR may stratify risk in EEC and are prioritized for further investigation.

Adipokines Deregulate Cellular Communication via Epigenetic Repression of Gap Junction Loci in Obese Endometrial Cancer.

Emerging evidence indicates that adipose stromal cells (ASC) are recruited to enhance cancer development. In this study, we examined the role these adipocyte progenitors play relating to intercellular communication in obesity-associated endometrial cancer. This is particularly relevant given that gap junctions have been implicated in tumor suppression. Examining the effects of ASCs on the transcriptome of endometrial epithelial cells (EEC) in an in vitro coculture system revealed transcriptional repression of GJA1 (encoding the gap junction protein Cx43) and other genes related to intercellular communication. This repression was recapitulated in an obesity mouse model of endometrial cancer. Furthermore, inhibition of plasminogen activator inhibitor 1 (PAI-1), which was the most abundant ASC adipokine, led to reversal of cellular distribution associated with the GJA1 repression profile, suggesting that PAI-1 may mediate actions of ASC on transcriptional regulation in EEC. In an endometrial cancer cohort (n = 141), DNA hypermethylation of GJA1 and related loci TJP2 and PRKCA was observed in primary endometrial endometrioid tumors and was associated with obesity. Pharmacologic reversal of DNA methylation enhanced gap-junction intercellular communication and cell-cell interactions in vitro. Restoring Cx43 expression in endometrial cancer cells reduced cellular migration; conversely, depletion of Cx43 increased cell migration in immortalized normal EEC. Our data suggest that persistent repression by ASC adipokines leads to promoter hypermethylation of GJA1 and related genes in the endometrium, triggering long-term silencing of these loci in endometrial tumors of obese patients. SIGNIFICANCE: Studies reveal that adipose-derived stem cells in endometrial cancer pathogenesis influence epigenetic repression of gap junction loci, which suggests targeting of gap junction activity as a preventive strategy for obesity-associated endometrial cancer.

Mismatch repair deficiency identifies patients with high-intermediate-risk (HIR) endometrioid endometrial cancer at the highest risk of recurrence: A prognostic biomarker.

BACKGROUND: The objective of this study was to assess the correlation between mismatch repair (MMR) status, disease recurrence patterns, and recurrence-free survival (RFS) in patients with high-intermediate-risk (HIR) endometrioid endometrial cancer (EEC). METHODS: A single-institution chart review for consecutive patients who were diagnosed with ECC between 2007 and 2016 was undertaken. Tumor MMR status was determined for all patients based on reported findings for mutL homolog 1 (MLH1), postmeiotic segregation (PMS2), mutS homolog 2 (MSH2), and MSH6 immunohistochemistry; and defective MMR (dMMR) status was defined as the lack of expression of at least 1 of these proteins. Patients were classified with HIR EEC according to criteria used for Gynecologic Oncology Group study 249. The factors associated with recurrence were assessed by logistic regression. RFS and associated factors were assessed by Kaplan-Meier survival analysis and Cox proportional-hazards models. RESULTS: In total, 197 patients who had HIR EEC (64 with dMMR and 133 with intact MMR [iMMR]) were identified, of whom 32 (16.2%) developed recurrent disease. The median follow-up was 54 months. The recurrence rate for women who had dMMR was 28% compared with 10.5% for those who had iMMR (P = .002), independent of the type of adjuvant therapy they received. The increase in distant recurrences among patients who had dMMR was even more pronounced (14.1% vs 3%; P = .003). The estimated 5-year RFS was 66% for women who had dMMR compared with 89% for those who had iMMR (P = .001). Excluding isolated vaginal recurrences, the difference in 5-year RFS was 73.5% versus 95%, respectively (P = .0004). CONCLUSIONS: Patients who had HIR EEC with dMMR had increased rates of recurrence and decreased RFS compared with those who had HIR EEC with iMMR, despite the receipt of similar adjuvant treatment. The current findings highlight the need for alternative treatment options and the importance of MMR status as a biomarker for patients with HIR EEC.

Functional characterization of recurrent FOXA2 mutations seen in endometrial cancers.

FOXA2, a member of the forkhead family of DNA-binding proteins, is frequently mutated in uterine cancers. Most of the mutations observed in uterine cancers are frameshifts and stops. FOXA2 is considered to be a driver gene in uterine cancers, functioning as a haploinsufficient tumor suppressor. The functional consequences of FOXA2 mutations, however, have not yet been determined. We evaluated the effects that frameshift mutations and a recurrent missense mutation have on FOXA2 transcriptional activity. Recurrent N-terminal frameshifts resulted in truncated proteins that failed to translocate to the nucleus and have no transcriptional activity using an E-cadherin/luciferase reporter assay. Protein abundance was reduced for the recurrent p.S169 W mutation, as was transcriptional activity. A C-terminal frameshift mutation had increased FOXA2 levels evidenced by both Western blot and immunofluorescence. Given that FOXA2 is a recognized activator of E-cadherin (CDH1) expression and E-cadherin's potential role in epithelial-to-mesenchymal transition in a wide range of cancer types, we tested the hypothesis that FOXA2 mutations in primary uterine cancer specimens would be associated with reduced CDH1 transcript levels. qRT-PCR revealed significantly lower levels of CDH1 expression in primary tumors with FOXA2 mutations. Our findings in vitro and in vivo suggest that reduced transcriptional activity associated with FOXA2 mutations in uterine cancers is likely to contribute to protumorigenic changes in gene expression.

Assessment of Tumor Sequencing as a Replacement for Lynch Syndrome Screening and Current Molecular Tests for Patients With Colorectal Cancer.

Importance: Universal tumor screening for Lynch syndrome (LS) in colorectal cancer (CRC) is recommended and involves up to 6 sequential tests. Somatic gene testing is performed on stage IV CRCs for treatment determination. The diagnostic workup for patients with CRC could be simplified and improved using a single up-front tumor next-generation sequencing test if it has higher sensitivity and specificity than the current screening protocol. Objective: To determine whether up-front tumor sequencing (TS) could replace the current multiple sequential test approach for universal tumor screening for LS. Design, Setting, and Participants: Tumor DNA from 419 consecutive CRC cases undergoing standard universal tumor screening and germline genetic testing when indicated as part of the multicenter, population-based Ohio Colorectal Cancer Prevention Initiative from October 2015 through February 2016 (the prospective cohort) and 46 patients with CRC known to have LS due to a germline mutation in a mismatch repair gene from January 2013 through September 2015 (the validation cohort) underwent blinded TS. Main Outcomes and Measures: Sensitivity of TS compared with microsatellite instability (MSI) testing and immunohistochemical (IHC) staining for the detection of LS. Results: In the 465 patients, mean age at diagnosis was 59.9 years (range, 20-96 years), and 241 (51.8%) were female. Tumor sequencing identified all 46 known LS cases from the validation cohort and an additional 12 LS cases from the 419-member prospective cohort. Testing with MSI or IHC, followed by BRAF p.V600E testing missed 5 and 6 cases of LS, respectively. Tumor sequencing alone had better sensitivity (100%; 95% CI, 93.8%-100%) than IHC plus BRAF (89.7%; 95% CI, 78.8%-96.1%; P = .04) and MSI plus BRAF (91.4%; 95% CI, 81.0%-97.1%; P = .07). Tumor sequencing had equal specificity (95.3%; 95% CI, 92.6%-97.2%) to IHC plus BRAF (94.6%; 95% CI, 91.9%-96.6%; P > .99) and MSI plus BRAF (94.8%; 95% CI, 92.2%-96.8%; P = .88). Tumor sequencing identified 284 cases with KRAS, NRAS, or BRAF mutations that could affect therapy for stage IV CRC, avoiding another test. Finally, TS identified 8 patients with germline DPYD mutations that confer toxicity to fluorouracil chemotherapy, which could also be useful for treatment selection. Conclusions and Relevance: Up-front TS in CRC is simpler and has superior sensitivity to current multitest approaches to LS screening, while simultaneously providing critical information for treatment selection.

STAT3/PIAS3 Levels Serve as "Early Signature" Genes in the Development of High-Grade Serous Carcinoma from the Fallopian Tube.

The initial molecular events that lead to malignant transformation of the fimbria of the fallopian tube (FT) through high-grade serous ovarian carcinoma (HGSC) remain poorly understood. In this study, we report that increased expression of signal transducer and activator of transcription 3 (pSTAT3 Tyr705) and suppression or loss of protein inhibitor of activated STAT3 (PIAS3) in FT likely drive HGSC. We evaluated human tissues-benign normal FT, tubal-peritoneal junction (TPJ), p53 signature FT tissue, tubal intraepithelial lesion in transition (TILT), serous tubal intraepithelial carcinoma (STIC) without ovarian cancer, and HGSC for expression of STAT3/PIAS3 (compared with their known TP53 signature) and their target proliferation genes. We observed constitutive activation of STAT3 and low levels or loss of PIAS3 in the TPJ, p53 signature, TILT, and STIC through advanced stage IV (HGSC) tissues. Elevated expression of pSTAT3 Tyr705 and decreased levels of PIAS3 appeared as early as TPJ and the trend continued until very advanced stage HGSC (compared with high PIAS3 and low pSTAT3 expression in normal benign FT). Exogenous expression of STAT3 in FT cells mediated translocation of pSTAT3 and c-Myc into the nucleus. In vivo experiments demonstrated that overexpression of STAT3 in FT secretory epithelial cells promoted tumor progression and metastasis, mimicking the clinical disease observed in patients with HGSC. Thus, we conclude that the STAT3 pathway plays a role in the development and progression of HGSC from its earliest premalignant states.Significance: Concomitant gain of pSTAT3 Tyr705 and loss of PIAS3 appear critical for initiation and development of high-grade serous carcinoma. Cancer Res; 78(7); 1739-50. ©2018 AACR.

The FOXA2 transcription factor is frequently somatically mutated in uterine carcinosarcomas and carcinomas.

BACKGROUND: Uterine carcinosarcomas (UCSs) are a rare but clinically aggressive form of cancer. They are biphasic tumors consisting of both epithelial and sarcomatous components. The majority of uterine carcinosarcomas are clonal, with the carcinomatous cells undergoing metaplasia to give rise to the sarcomatous component. The objective of the current study was to identify novel somatically mutated genes in UCSs. METHODS: We whole exome sequenced paired tumor and nontumor DNAs from 14 UCSs and orthogonally validated 464 somatic variants using Sanger sequencing. Fifteen genes that were somatically mutated in at least 2 tumor exomes were Sanger sequenced in another 39 primary UCSs. RESULTS: Overall, among 53 UCSs in the current study, the most frequently mutated of these 15 genes were tumor protein p53 (TP53) (75.5%), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) (34.0%), protein phosphatase 2, regulatory subunit A, alpha (PPP2R1A) (18.9%), F-box and WD repeat domain containing 7 (FBXW7) (18.9%), chromodomain helicase DNA binding protein 4 (CHD4) (17.0%), and forkhead box A2 (FOXA2) (15.1%). FOXA2 has not previously been implicated in UCSs and was predominated by frameshift and nonsense mutations. One UCS with a FOXA2 frameshift mutation expressed truncated FOXA2 protein by immunoblotting. Sequencing of FOXA2 in 160 primary endometrial carcinomas revealed somatic mutations in 5.7% of serous, 22.7% of clear cell, 9% of endometrioid, and 11.1% of mixed endometrial carcinomas, the majority of which were frameshift mutations. CONCLUSIONS: Collectively, the findings of the current study provide compelling genetic evidence that FOXA2 is a pathogenic driver gene in the etiology of primary uterine cancers, including UCSs. Cancer 2018;124:65-73. © 2017 American Cancer Society.