Impact of an immunohistochemistry-based universal screening protocol for Lynch syndrome in endometrial cancer on genetic counseling and testing

Delivery of hereditary cancer genetics services to patients newly diagnosed with ovarian and endometrial cancers at three gynecologic oncology clinics in the USA, Brazil, and Mexico

OBJECTIVE

Three gynecologic oncology clinics located in the USA, Brazil, and Mexico collaborated to evaluate their delivery of hereditary cancer genetics services. This descriptive retrospective review study aimed to establish baseline rates and timeliness of guideline-recommended genetics service delivery to patients with ovarian, fallopian tube, primary peritoneal (ovarian), and endometrial cancers at each clinic.

METHODS

Patients who were newly diagnosed with ovarian and endometrial cancers between September 1, 2018 and December 31, 2020 were identified from the medical records of the clinics. Genetics service delivery metrics included the rates of mismatch repair deficiency tumor testing for patients with endometrial cancer (microsatellite instability/immunohistochemistry, MSI/IHC), referral to genetics services for patients with ovarian cancer, completed genetics consultations, and germline genetic testing for patients with ovarian and endometrial cancers. Timeliness was calculated as the average number of days between diagnosis and the relevant delivery metric. Descriptive statistics were used to analyze data.

RESULTS

In total, 1195 patients (596 with ovarian cancer, 599 with endometrial cancer) were included in the analysis, and rates of genetics service delivery varied by clinic. For patients with ovarian cancer, referral rates ranged by clinic from 32.6% to 89.5%; 30.4-65.1% of patients completed genetics consultation and 32.6-68.7% completed genetic testing. The timeliness to genetic testing for patients with ovarian cancer ranged by clinic from 107 to 595 days. A smaller proportion of patients with endometrial cancer completed MSI/IHC testing (10.0-69.2%), with the average time to MSI/IHC ranging from 15 to 282 days. Rates of genetics consultation among patients with endometrial cancer ranged by clinic from 10.8% to 26.0% and 12.5-16.6% completed genetic testing.

CONCLUSIONS

All clinics successfully established baseline rates and timeliness of delivering hereditary cancer genetics services to patients with ovarian and endometrial cancers. Lower rates of delivering genetics services to patients with endometrial cancer warrant additional research and quality improvement efforts.

A tale of two pathways: Review of immune checkpoint inhibitors in DNA mismatch repair-deficient and microsatellite instability-high endometrial cancers

The DNA mismatch repair (MMR) pathway is critical for correcting DNA mismatches generated during DNA replication. MMR-deficiency (MMR-D) leads to microsatellite instability (MSI) associated with an increased mutation rate, driving cancer development. This is particularly relevant in endometrial cancer (EC) as 25%-30% of tumors are of MMR-D/MSI-high (MSI-H) phenotype. Comprehensive assessment using immunohistochemistry (IHC) and sequencing-based techniques are necessary to fully evaluate ECs given the importance of molecular subtyping in staging and prognosis. This also influences treatment selection as clinical trials have demonstrated survival benefits for immune checkpoint inhibitors (ICIs) alone and in combination with chemotherapy for MMR-D/MSI-H EC patients in various treatment settings. As a portion of MMR-D/MSI-H ECs are driven by Lynch syndrome, an inherited cancer predisposition syndrome that is also associated with colorectal cancer, this molecular subtype also prompts germline assessment that can affect at-risk family members. Additionally, heterogeneity in the tumor immune microenvironment and tumor mutation burden (TMB) have been described by MMR mechanism, meaning MLH1 promoter hypermethylation versus germline/somatic MMR gene mutation, and this may affect response to ICI therapies. Variations by ancestry in prevalence and mechanism of MMR-D/MSI-H tumors have also been reported and may influence health disparities given observed differences in tumors of Black compared to White patients which may affect ICI eligibility. These observations highlight the need for additional prospective studies to evaluate the nuances regarding MMR-D heterogeneity as well as markers of resistance to inform future trials of combination therapies to further improve outcomes for patients with EC.

Clinical features and impact of p53 status on sporadic mismatch repair deficiency and Lynch syndrome in uterine cancer

The clinical features of sporadic mismatch repair deficiency (MMRd) and Lynch syndrome (LS) in Japanese patients with endometrial cancer (EC) were examined by evaluating the prevalence and prognostic factors of LS and sporadic MMRd in patients with EC. Targeted sequencing of five LS susceptibility genes (MLH1, MSH2, MSH6, PMS2, and EPCAM) was carried out in 443 patients with EC who were pathologically diagnosed with EC at the National Cancer Center Hospital between 2011 and 2018. Pathogenic variants in these genes were detected in 16 patients (3.7%). Immunohistochemistry for MMR proteins was undertaken in 337 of the 433 (77.9%) EC patients, and 91 patients (27.0%) showed absent expression of at least one MMR protein. The 13 cases of LS with MMR protein loss (93.8%) showed a favorable prognosis with a 5-year overall survival (OS) rate of 100%, although there was no statistically significant difference between this group and the sporadic MMRd group (p = 0.27). In the MMRd without LS group, the 5-year OS rate was significantly worse in seven patients with an aberrant p53 expression pattern than in those with p53 WT (53.6% vs. 93.9%, log-rank test; p = 0.0016). These results suggest that p53 abnormalities and pathogenic germline variants in MMR genes could be potential biomarkers for the molecular classification of EC with MMRd.

Discordant Staining Patterns and Microsatellite Results in Tumors of MSH6 Pathogenic Variant Carriers

Diagnosis of Lynch syndrome (LS) caused by a pathogenic germline MSH6 variant may be complicated by discordant immunohistochemistry (IHC) and/or by a microsatellite stable (MSS) phenotype. This study aimed to identify the various causes of the discordant phenotypes of colorectal cancer (CRC) and endometrial cancer (EC) in MSH6-associated LS. Data were collected from Dutch family cancer clinics. Carriers of a (likely) pathogenic MSH6 variant diagnosed with CRC or EC were categorized based on an microsatellite instability (MSI)/IHC test outcome that might fail to result in a diagnosis of LS (eg, retained staining of all 4 mismatch repair proteins, with or without an MSS phenotype, and other staining patterns). When tumor tissue was available, MSI and/or IHC were repeated. Next-generation sequencing (NGS) was performed in cases with discordant staining patterns. Data were obtained from 360 families with 1763 (obligate) carriers. MSH6 variant carriers with CRC or EC (n = 590) were included, consisting of 418 CRCs and 232 ECs. Discordant staining was reported in 77 cases (36% of MSI/IHC results). Twelve patients gave informed consent for further analysis of tumor material. Upon revision, 2 out of 3 MSI/IHC cases were found to be concordant with the MSH6 variant, and NGS showed that 4 discordant IHC results were sporadic rather than LS-associated tumors. In 1 case, somatic events explained the discordant phenotype. The use of reflex IHC mismatch repair testing, the current standard in most Western countries, may lead to the misdiagnosis of germline MSH6 variant carriers. The pathologist should point out that further diagnostics for inheritable colon cancer, including LS, should be considered in case of a strong positive family history. Germline DNA analysis of the mismatch repair genes, preferably as part of a larger gene panel, should therefore be considered in potential LS patients.

Improving genetic testing following abnormal mismatch repair immunohistochemistry results in endometrial cancer

OBJECTIVES

Although universal mismatch repair (MMR) immunohistochemistry (IHC) in endometrial cancer began at our institution in July 2015, not all eligible patients were referred for genetic testing (GT). In April 2017, genetic counselors obtained IHC data and contacted physicians to approve genetic counseling referrals (GCRs) for Lynch Syndrome (LS) in eligible patients. We assessed if this protocol increased frequency of GCRs and GT in patients with abnormal MMR IHC.

METHODS

We retrospectively (7/2015-5/2022) identified patients with abnormal MMR IHC at a large urban hospital. GCRs and GT were compared between cases from 7/2015-4/2017 (pre-protocol) and 5/2017-5/2022 (post-protocol) with chi-square and Fisher's exact tests.

RESULTS

Of 794 patients with IHC testing, 177 (22.3%) had abnormal MMR results with 46 (26.0%) meeting criteria for LS screening with GT. Of 46 patients, 16 (34.8%) were identified prior to and 30 (65.2%) after the protocol initiation. GCRs significantly increased from 11/16 (68.8%) to 29/30 (96.7%) in the pre-protocol versus post-protocol groups, p = 0.02. There was no statistically significant difference in GT between groups (10/16, 62.5% vs 26/30, 86.7%, p = 0.07). Of 36 patients who underwent GT, 16 (44.4%) had LS: MSH6, 9; MSH2, 4; PMS2, 2; MLH1, 1.

CONCLUSIONS

Increased frequency of GCRs was observed following the change in protocol, which is important as LS screening has clinical implications for patients and their families. Despite this additional effort, approximately 15% who met criteria did not undergo GT; further efforts such as universal germline testing in patients with endometrial cancer should be considered.

Data Set for the Reporting of Endometrial Cancer: Recommendations From the International Collaboration on Cancer Reporting (ICCR)

Endometrial cancer is one of the most common cancers among women. The International Collaboration on Cancer Reporting (ICCR) developed a standardized endometrial cancer data set in 2011, which provided detailed recommendations for the reporting of resection specimens of these neoplasms. A new data set has been developed, which incorporates the updated 2020 World Health Organization Classification of Female Genital Tumors, the Cancer Genome Atlas (TCGA) molecular classification of endometrial cancers, and other major advances in endometrial cancer reporting, all of which necessitated a major revision of the data set. This updated data set has been produced by a panel of expert pathologists and an expert clinician and has been subject to international open consultation. The data set includes core elements which are unanimously agreed upon as essential for cancer diagnosis, clinical management, staging, or prognosis and noncore elements which are clinically important, but not essential. Explanatory notes are provided for each element. Adoption of this updated data set will result in improvements in endometrial cancer patient care.

Genomic instability and the link to infertility: A focus on microsatellites and genomic instability syndromes

Infertility is associated to multiple types of different genomic instabilities and is a genetic feature of genomic instability syndromes. While the mismatch repair machinery contributes to the maintenance of genome integrity, surprisingly its potential role in infertility is overlooked. Defects in mismatch repair mechanisms contribute to microsatellite instability and genomic instability syndromes, due to the inability to repair newly replicated DNA. This article reviews the literature to date to elucidate the contribution of microsatellite instability to genomic instability syndromes and infertility. The key findings presented reveal microsatellite instability is poorly researched in genomic instability syndromes and infertility.

Interventions to improve delivery of cancer genetics services in the United States: A scoping review

PURPOSE

Interventions that decrease barriers and improve clinical processes can increase patient access to guideline-recommended cancer genetics services. We sought to identify and describe interventions to improve patient receipt of guideline-recommended cancer genetics services in the United States.

METHODS

We performed a comprehensive search in Ovid MEDLINE and Embase, Scopus, and Web of Science from January 1, 2000 to February 12, 2020. Eligible articles reported interventions to improve the identification, referral, genetic counseling (GC), and genetic testing (GT) of patients in the United States. We independently screened titles and abstracts and reviewed full-text articles. Data were synthesized by grouping articles by clinical process.

RESULTS

Of 44 included articles, 17 targeted identification of eligible patients, 14 targeted referral, 15 targeted GC, and 16 targeted GT. Patient identification interventions included universal tumor testing and screening of medical/family history. Referral interventions included medical record system adaptations, standardizing processes, and provider notifications. GC interventions included supplemental patient education, integrated GC within oncology clinics, appointment coordination, and alternative service delivery models. One article directly targeted the GT process by implementing provider-coordinated testing.

CONCLUSION

This scoping review identified and described interventions to improve US patients' access to and receipt of guideline-recommended cancer genetics services.

Endometrial cancer in Lynch syndrome

Lynch syndrome (LS) is an autosomal dominant inherited disease caused by germline pathogenic variants (PVs) in mismatch repair (MMR) genes. LS-associated endometrial cancer (LS-EC) is the most common extraintestinal sentinel cancer caused by germline PVs in MMR genes, including MLH1, MSH2, MSH6 and PMS2. The clinicopathologic features of LS-EC include early age of onset, lower body mass index (BMI), endometrioid carcinoma and lower uterine segment involvement. There has been significant progress in screening, diagnosis, surveillance, prevention and treatment of LS-EC. Many studies support universal screening for LS among patients with EC. Screening mainly involves a combination of traditional clinical criteria and molecular techniques, including MMR-immunohistochemistry (MMR-IHC), microsatellite instability (MSI) testing, MLH1 promoter methylation testing and gene sequencing. The effectiveness of endometrial biopsy and transvaginal ultrasound (TVS) for clinical monitoring of asymptomatic women with LS are uncertain yet. Preventive strategies include hysterectomy and bilateral salpingo-oophorectomy (BSO) as well as chemoprophylaxis using exogenous progestin or aspirin. Recent research has revealed the benefits of immunotherapy for LS-EC. The NCCN guidelines recommend pembrolizumab and nivolumab for treating patients with advanced or recurrent microsatellite instability-high (MSI-H)/mismatch repair-deficient (dMMR) EC.

Defining Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Placentitis: A Report of 7 Cases with Confirmatory In Situ Hybridization, Distinct Histomorphologic Features, and Evidence of Complement Deposition

CONTEXT

-Case reports and rare case series have demonstrated variable placental pathology in the setting of maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In rare small studies demonstrating infection of the placental parenchyma, histologic manifestations have included variable degrees of histiocytic intervillositis, perivillous fibrin deposition, and syncytiotrophoblast necrosis.

OBJECTIVE

-To characterize the placental pathological features of SARS-CoV-2 infected placentas, irrespective of fetal-maternal transmission, and to examine the frequency of C4d activation in such cases.

DESIGN

-Retrospective study of seven placentas from mothers with active SARS-CoV-2 infection and placental infection as demonstrated by RNA in situ hybridization.

RESULTS

-Six placentas were from live-born neonates (5 singletons, 1 non-fused diamniotic-dichorionic twin placenta), and one was from a stillbirth. Five of the eight neonates (including the stillbirth) tested negative for SARS-CoV-2, and all were negative for neonatal infection. The remaining three neonates were well at time of discharge. All placentas were positive for SARS-CoV-2 infection by RNA in situ hybridization and demonstrated variable degrees of histiocytic intervillositis, perivillous fibrin deposition, and trophoblast necrosis. Three cases demonstrated features of fetal vascular malperfusion. CD68 highlighted intervillous histiocytes. C4d expression was present along the villous borders in 6 of 7 cases.

CONCLUSIONS

-SARS-CoV-2 placentitis is defined by the triad of histiocytic intervillositis, perivillous fibrin deposition, and trophoblast necrosis. The features may occur in cases without confirmed transplacental transmission. The damage caused by SARS-CoV-2 placentitis is likely mediated by complement activation.

Cancer Genomic Profiling in Colorectal Cancer: Current Challenges in Subtyping Colorectal Cancers Based on Somatic and Germline Variants

Colorectal cancer (CRC) is a heterogeneous disease caused by the accumulation of multistep genetic alterations under the influence of genomic instability. Different backgrounds of genomic instability, such as chromosomal instability, microsatellite instability, hypermutated-single nucleotide variants, and genome stable-induced transformation in the colonic epithelium, can result in adenomas, adenocarcinomas, and metastatic tumors. Characterization of molecular subtypes and establishment of treatment policies based on each subtype will lead to better treatment outcomes and an improved selection of molecularly targeted agents. In Japan, cancer precision medicine has been introduced in the National Health Insurance program through the addition of the cancer genomic profiling (CGP) examination. It has also become possible to access a large amount of genomic information, including information on pathogenic somatic and germline variants, incomparable to conventional diagnostic tests. This information enables us to apply research data to clinical decision-making, benefiting patients and their healthy family members. In this article, we discuss the important molecules and signaling pathways presumed to be the driver genes of CRC progression and the signal transduction system in which they are involved. Molecular subtypes of CRC based on CGP examinations and gene expression profiles have been established in The Cancer Genome Atlas Network with the advent of next-generation sequencing technology. We will also discuss the recommended management of secondary/germline findings, pathogenic germline variants, and presumed germline pathogenic variants obtained from CGP examination and review the current challenges to better understand these data in a new era of cancer genomic medicine.

Lost opportunities for mismatch repair (MMR) screening among minority women with endometrial cancer

Lynch Syndrome (LS) prevalence in underrepresented minorities are lacking. The objective of this study was to assess the prevalence of LS in a minority patient population. Secondary objectives included identifying factors associated with successful LS screening and to characterize clinicopathologic features. Women with endometrial cancer treated within a university system from 2014 and 2016 were included. Immunohistochemistry (IHC) results of MLH1, PMS2, MSH2 and MSH6 were obtained from medical records and clinicopathologic factors abstracted. Patients not previously screened for LS were screened. 276 patients were evaluable. More minority women were screened as part of their routine cancer care (p = 0.005). Additionally, women 50 years or younger were more likely to be screened for LS compared to women older than 51(p = 0.009) and uninsured or reliant on Medicaid patients (p = 0.011) were more likely to be screened during routine care. Six patients received confirmatory germline testing for LS (4.3%), and another 8 patients had a staining pattern suggestive of LS. In an underrepresented population, the rate of LS in endometrial cancer is similar to previous reports. LS may be under diagnosed and opportunities missed when universal screening is not applied in minority women.

Prevalence and molecular characteristics of DNA mismatch repair deficient endometrial cancer in a Japanese hospital-based population

BACKGROUND

The prevalence and molecular characteristics of defective DNA mismatch repair endometrial cancers in the Japanese population have been underexplored. Data supporting clinical management of patients with Lynch-like syndrome and germline variant of uncertain significance of mismatch repair genes are still lacking.

METHODS

Immunohistochemistry of mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2) was performed on formalin-fixed paraffin-embedded sections prepared from resected primary endometrial cancers in 395 women with a median age of 59 years. Genetic and/or epigenetic alterations of the mismatch repair genes were also investigated.

RESULTS

Loss of expression of one or more mismatch repair proteins was observed in 68 patients (17.2%). A total of 17 out of 68 patients (25%, 4.3% of all cases) were identified as candidates for genetic testing for Lynch syndrome after excluding 51 patients with MLH1 hypermethylated cancer. Fourteen of these 17 patients subjected to genetic testing were found to have Lynch syndrome (n = 5), germline variant of uncertain significance (n = 2) or Lynch-like syndrome (n = 7). Compared with patients with Lynch syndrome, those with germline variant of uncertain significance and Lynch-like syndrome tended to demonstrate an older age at the time of endometrial cancer diagnosis (P = 0.07), less fulfillment of the revised Bethesda guidelines (P = 0.09) and lower prevalence of Lynch syndrome-associated tumors in their first-degree relatives (P = 0.01).

CONCLUSIONS

This study provides useful information for management in patients with DNA mismatch repair endometrial cancer. Specifically, cancer surveillance as recommended in patients with Lynch syndrome might not be necessary in patients with germline variant of uncertain significance and Lynch-like syndrome and their relatives.

Evaluation of a nationwide Dutch guideline to detect Lynch syndrome in patients with endometrial cancer

OBJECTIVE

In the Netherlands a nationwide guideline was introduced in 2016, which recommended routine Lynch syndrome screening (LSS) for all women with endometrial cancer (EC) <70 years of age. LSS consists of immunohistochemical (IHC) staining for loss of mismatch repair (MMR) protein expression, supplemented with MLH1 methylation analysis if indicated. Test results are evaluated by the treating gynaecologist, who refers eligible patients to a clinical geneticist. We evaluated the implementation of this guideline.

METHODS

From the nation-wide pathology database we selected all women diagnosed with EC < 70 years of age, treated from 1.6.2016-1.6.2017 in 14 hospitals. We collected data on the results of LSS and follow up of cases with suspected LS.

RESULTS

In 183 out of 204 tumours (90%) LSS was performed. In 41 cases (22%) MMR protein expression was lost, in 25 cases due to hypermethylation of the MLH1 promotor. One patient was known with a pathogenic MLH1 variant. The option of genetic counselling was discussed with 12 of the 15 remaining patients, of whom three declined. After counselling by the genetic counsellor nine patients underwent germline testing. In two no pathogenic germline variant was detected, two were diagnosed with a pathogenic PMS2 variant, and five with a pathogenic MSH6 variant, in concordance with the IHC profiles.

CONCLUSION

Coverage of LSS was high (90%), though referral for genetic counselling could be improved. Gynaecologists ought to be aware of the benefits and possible drawbacks of knowing mutational status, and require training in discussing this with their patients.

Evaluating the impact of universal Lynch syndrome screening in a publicly funded healthcare system

PURPOSE

Referrals for Lynch syndrome (LS) assessment have traditionally been based on personal and family medical history. The introduction of universal screening practices has allowed for referrals based on immunohistochemistry tests for mismatch repair (MMR) protein expression. This study aims to characterize the effect of universal screening in a publicly funded healthcare system with comparison to patients referred by traditional criteria, from January 2012 to March 2017.

METHODS

Patient files from the time of initiation of universal screening from 2012 to 2017 were reviewed. Patients were sorted into two groups: (a) universally screened and (b) referred by traditional methods. Mutation detection rates, analysis of traditional testing criteria met, and cascade carrier testing were evaluated.

RESULTS

The mutation detection rate of the universal screening group was higher than the traditionally referred group (45/228 (19.7%) vs 50/390 (12.5%), P = .05), though each were able to identify unique patients. An analysis of testing criteria met by each patient showed that half of referred patients from the universal screening group could not meet any traditional testing criteria.

CONCLUSION

The implementation of universal screening in a publicly funded system will increase efficiency in detecting patients with LS. The resources available for genetic testing and counseling may be more limited in public systems, thus inclusion of secondary screening with BRAF and MLH1 promoter hypermethylation testing is key to further optimizing efficiency.

Variation in physician-directed immunohistochemistry screening among women with endometrial cancer

Objective

Immunohistochemistry screening is a reliable method for identifying women with endometrial cancer who are at risk for Lynch syndrome, but clinical workflows used to implement immunohistochemistry screening protocols can vary by institution. The goal of this study was to investigate variation in performance of immunohistochemistry screening when a physician order is required.

Methods

Retrospective study from an integrated healthcare system with a risk-based immunohistochemistry screening policy for Lynch syndrome from January 2015 to December 2016. Immunohistochemistry screening was indicated for all women with endometrial cancer aged <60 years and women with endometrial cancer aged ≥60 years who had a personal/family history suggestive of Lynch syndrome. However, a physician order was needed to have immunohistochemistry screening performed on the tumor specimen as our health system did not have reflex screening in the clinical workflow. Demographics and tumor characteristics were reviewed, and patients were stratified by immunohistochemistry screening status. Multivariable regression was performed to identify factors associated with immunohistochemistry performance and reported as odds ratios (ORs) with 95% confidence intervals (CIs).

Results

There were 1399 eligible patients in the study. With a required physician order, immunohistochemistry screening rates (20% overall, 34% aged <60 years) were significantly lower than previous reports (36% overall, 90% aged <60 years, p≤0.0001 for both comparisons). Significant factors associated with immunohistochemistry screening performance identified by multivariable analysis included age, race, body mass index, personal/family cancer history, diabetes, endometrioid histology, and tumor grade. Asian women were most likely to have immunohistochemistry screening (OR 1.58, 95% CI 1.07 to 2.34) whereas black women were least likely (OR 0.43, 95% CI 0.22 to 0.91).

Conclusions

Immunohistochemistry screening rates in women with endometrial cancer were lower in our health system compared with prior reports in the literature, and there were variations in screening performance according to patient age, race, and body mass index. Requiring a physician order for immunohistochemistry screening likely creates a barrier in screening uptake, therefore automated immunohistochemistry screening is recommended.

Comparison of two Lynch screening strategies in endometrial cancer in a California health system

OBJECTIVE

Compare detection of Lynch syndrome in endometrial cancer between regions of a health care system with different screening strategies.

METHODS

A retrospective study of endometrial cancer (EC) cases from 2 regions of an integrated health care system (Kaiser Permanente Northern (KPNC) and Southern (KPSC) California). Within KPNC, immunohistochemistry tumor screening (IHC) was physician ordered and risk-based; within KPSC, IHC was universal and automated. Clinical risk factors associated with abnormal IHC and Lynch Syndrome (LS) were identified.

RESULTS

During the study, there were 2045 endometrial cancers: 1399 in the physician-order group and 646 in the universal testing group. In the physician-order group: among women < age 60, 34% underwent IHC; 9.6% were abnormal, and 3% were possible LS after methylation testing; among women ≥60, 11% underwent IHC, 3% were abnormal and <1% were possible LS. In the universal group, 87% of women age <60 had IHC, 19.4% were abnormal, and 6% were possible LS; Among women age ≥60, 82% underwent IHC, 26% were abnormal, and 2% were possible LS. There were no differences in LS cases between the physician-order group and the universal group in either age strata (<60: 3% vs. 3.6%, p=0.62; ≥60: <1% vs. 1%, p=0.63) Factors associated with LS were younger age (odds ratio (OR) 0.11, 95% confidence interval (CI) 0.04-0.29) and lower body mass index (BMI), (OR 0.38 95% CI 0.18-0.80).

CONCLUSIONS

Universal IHC screening did not result in increased LS detection in EC.

Utility of the immunohistochemical analysis of DNA mismatch-repair proteins in endometrial hyperplasia

The utility of the expression lack of DNA mismatch-repair (MMR) proteins in the detection of Lynch syndrome in endometrial hyperplasia as precursor lesion of endometrial carcinoma has not been well-established. The study investigated the immunoexpression pattern of MMR proteins in endometrial hyperplasia from Tunisian patients. We carried out a retrospective study of 60 endometrial hyperplasias diagnosed among Tunisian patients. Expression of MLH1, MSH2, MSH6, and PMS2 proteins was performed by immunohistochemistry on whole-slide sections of archival tissues. Analysis of MLH1 promoter methylation and microsatellite alterations was conducted in appropriate cases. Microsatellite instability screening was assessed using the Bethesda panel, including BAT25, BAT26, D17S250, D2S123, and D5S346 markers. Expression of MMR proteins was observed in all hyperplasias without atypia as well as in 27 out of 29 atypical hyperplasias. Only two atypical hyperplasias exhibited expression loss of MMR proteins. A single case revealed MSH6 expression lack. Expression loss of MLH1 and PMS2 was identified in another atypical hyperplasia and was associated with hypermethylation of MLH1 promoter. This patient had no familial history of endometrial cancer at the diagnostic time. The two deficient MMR cases showed microsatellite stable pattern. In conclusion, only two endometrial hyperplasias displayed an altered pattern of MMR expression. Our results suggest the limited utility of the immunohistochemical analysis of MMR protein in the early detection of Lynch syndrome in Tunisian patients diagnosed with endometrial hyperplasias. Multicenter studies with larger sample size are needed to more explore these findings.

Effective Identification of Lynch Syndrome in Gastroenterology Practice

Purpose of review:

Identification of Lynch syndrome is important from an individual patient and public health standpoint. As paradigms for Lynch syndrome diagnosis have shifted in recent years, this review will discuss rationale and limitations for current strategies as well as provide an overview of future directions in the field.

Recent findings:

In recent years, the use of clinical criteria and risk scores for identification of Lynch syndrome have been augmented by universal testing of all newly diagnosed colorectal cancers with molecular methods to screen for mismatch repair deficiency with high sensitivity and specificity. Studies of implementation and outcomes of universal testing in clinical practice have demonstrated significant heterogeneity that results in suboptimal uptake and contributes to disparities in diagnosis. Emerging technologies, such as next-generation sequencing, hold significant promise as a screening strategy for Lynch syndrome.

Summary:

Universal testing for Lynch syndrome is being performed with increasing frequency, although real-world outcomes have demonstrated room for improvement. Future directions in Lynch syndrome diagnosis will involve optimization of universal testing workflow and application of new genetics technologies.

Universal tumor screening for Lynch syndrome: perspectives of Canadian pathologists and genetic counselors

Universal screening of all newly diagnosed colorectal cancer tumors can identify individuals at high risk for Lynch syndrome (LS), a hereditary cancer syndrome predisposing carriers to increased risk of colorectal, endometrial, and other cancers. To inform planning of a universal tumor screening program for LS in our jurisdiction, we undertook online surveys of Canadian pathologists and genetic counselors to describe existing tumor screening programs. Online surveys were hosted on SurveyMonkey between October 2016 and March 2017. Fifty-three pathologists and 66 genetic counselors completed surveys (total n = 119). While attitudes towards tumor screening were positive, considerable variability was observed in the existence of tumor screening, test ordering criteria, and practices. Most respondents indicated consent was not obtained for tumor screening nor were educational materials provided to patients; however, opting out of additional mutation testing in the event of a positive tumor screen was endorsed. Results add to the growing literature on providers' perspectives on population-based tumor screening programs and inform ways to offer these. Findings highlight the need to develop methods of patient education that allow meaningful opt-out decisions. The variability we observed also suggests the need for national standards and guidance on tumor screening for LS.

The proportion of endometrial cancers associated with Lynch syndrome: a systematic review of the literature and meta-analysis

Purpose

Endometrial cancer (EC) is often the sentinel cancer in women with Lynch syndrome (LS). However, efforts to implement universal LS screening in EC patients have been hampered by a lack of evidence detailing the proportion of EC patients that would be expected to screen positive for LS.

Methods

Studies were identified by electronic searches of Medline, Embase, Cochrane CENTRAL and Web of Science. Proportions of test positivity were calculated by random and fixed-effects meta-analysis models. I² score was used to assess heterogeneity across studies.

Results

Fifty-three studies, including 12,633 EC patients, met the inclusion criteria. The overall proportion of endometrial tumors with microsatellite instability or mismatch repair (MMR) deficiency by immunohistochemistry (IHC) was 0.27 (95% confidence interval [CI] 0.25–0.28, I²: 71%) and 0.26 (95% CI 0.25–0.27, I²: 88%), respectively. Of those women with abnormal tumor testing, 0.29 (95% CI 0.25–0.33, I²: 83%) had LS-associated pathogenic variants on germline testing; therefore around 3% of ECs can be attributed to LS. Preselection of EC cases did increase the proportion of germline LS diagnoses.

Conclusion

The current study suggests that prevalence of LS in EC patients is approximately 3%, similar to that of colorectal cancer patients; therefore our data support the implementation of universal EC screening for LS.

International Society of Gynecological Pathologists (ISGyP) Endometrial Cancer Project: Guidelines From the Special Techniques and Ancillary Studies Group

The aim of this article is to propose guidelines and recommendations in problematic areas in pathologic reporting of endometrial carcinoma (EC) regarding special techniques and ancillary studies. An organizing committee designed a comprehensive survey with different questions related to pathologic features, diagnosis, and prognosis of EC that was sent to all members of the International Society of Gynecological Pathologists. The special techniques/ancillary studies group received 4 different questions to be addressed. Five members of the group reviewed the literature and came up with recommendations and an accompanying text which were discussed and agreed upon by all members of the group. Twelve different recommendations are made. They address the value of immunohistochemistry, ploidy, and molecular analysis for assessing prognosis in EC, the value of steroid hormone receptor analysis to predict response to hormone therapy, and parameters regarding applying immunohistochemistry and molecular tests for assessing mismatch deficiency in EC.

Disparities in gynecologic cancer genetics evaluation

An estimated 2-5% of endometrial cancers and 15-20% of high-grade, non-mucinous epithelial ovarian cancers have an underlying hereditary cause. Appropriate risk assessment, genetic counseling, and germline genetic testing for cancer predisposition genes in both gynecologic cancer patients and their at-risk relatives is essential for effective delivery of tailored cancer treatment and cancer prevention. However, significant disparities exist within medically underserved and minority populations in the United States regarding awareness of, access to, and use of genetic services. The objectives of this review are to summarize the literature on genetic counseling and genetic testing of gynecologic cancer patients, the cascade genetic testing of their families following the identification of a germline mutation associated with susceptibility to cancer, to highlight disparities between populations, and to present some potential remedies.

Interpretation of Mismatch Repair Protein Immunohistochemistry in Endometrial Carcinoma Should Consider Both Lynch Syndrome Screening and Immunotherapy Susceptibility: An Illustrative Case Report

We present an instructive case of FIGO grade 1 endometrioid endometrial carcinoma with a biphasic morphology, corresponding to subclonal loss of mismatch repair proteins (MMRP) MLH1 and PMS2 by immunohistochemistry and subclonal microsatellite instability. A pulmonary metastasis represented only the tumor component with retention of MMRPs. This case illustrates the need for pathologists to recognize and report heterogenous expression of MMRPs in endometrial carcinoma, to consider tumor heterogeneity when selecting foci for molecular studies, and to re-evaluate MMRP expression in tumor metastases, when clinically indicated. These considerations are particularly important as the relevance of MMRP expression in endometrial cancer expands beyond Lynch syndrome screening, into a new role as a predictive marker for immunotherapy.

Low Referral Rate for Genetic Testing in Racially and Ethnically Diverse Patients Despite Universal Colorectal Cancer Screening

BACKGROUND & AIMS

Guidelines recommend that all colorectal tumors be assessed for mismatch repair deficiency, which could increase identification of patients with Lynch syndrome. This is of particular importance for minority populations, in whom hereditary syndromes are under diagnosed. We compared rates and outcomes of testing all tumor samples (universal testing) collected from a racially and ethnically diverse population for features of Lynch syndrome.

METHODS

We performed a retrospective analysis of colorectal tumors tested from 2012 through 2016 at 4 academic centers. Tumor samples were collected from 767 patients with colorectal cancer (52% non-Hispanic white [NHW], 26% African American, and 17% Hispanic patients). We assessed rates of tumor testing, recommendations for genetic evaluation, rates of attending a genetic evaluation, and performance of germline testing overall and by race/ethnicity. We performed univariate and multivariate regression analyses.

RESULTS

Overall, 92% of colorectal tumors were analyzed for mismatch repair deficiency without significant differences among races/ethnicities. However, minority patients were significantly less likely to be referred for genetic evaluation (21.2% for NHW patients vs 16.9% for African American patients and 10.9% for Hispanic patients; P = .02). Rates of genetic testing were also lower among minority patients (10.7% for NHW patients vs 6.0% for AA patients and 3.1% for Hispanic patients; P < .01). On multivariate analysis, African American race, older age, and medical center were independently associated with lack of referral for genetic evaluation and genetic testing.

CONCLUSION

In a retrospective analysis, we found that despite similar rates of colorectal tumor analysis, minority patients are less likely to be recommended for genetic evaluation or to undergo germline testing for Lynch syndrome. Improvements in institutional practices in follow up after tumor testing could reduce barriers to diagnosis of Lynch diagnosis in minorities.

Next-Generation Service Delivery: A Scoping Review of Patient Outcomes Associated with Alternative Models of Genetic Counseling and Genetic Testing for Hereditary Cancer

The combination of increased referral for genetic testing and the current shortage of genetic counselors has necessitated the development and implementation of alternative models of genetic counseling and testing for hereditary cancer assessment. The purpose of this scoping review is to provide an overview of the patient outcomes that are associated with alternative models of genetic testing and genetic counseling for hereditary cancer, including germline-only and tumor testing models. Seven databases were searched, selecting studies that were: (1) full-text articles published ≥2007 or conference abstracts published ≥2015, and (2) assessing patient outcomes of an alternative model of genetic counseling or testing. A total of 79 publications were included for review and synthesis. Data-charting was completed using a data-charting form that was developed by the study team for this review. Seven alternative models were identified, including four models that involved a genetic counselor: telephone, telegenic, group, and embedded genetic counseling models; and three models that did not: mainstreaming, direct, and tumor-first genetic testing models. Overall, these models may be an acceptable alternative to traditional models on knowledge, patient satisfaction, psychosocial measures, and the uptake of genetic testing; however, particular populations may be better served by traditional in-person genetic counseling. As precision medicine initiatives continue to advance, institutions should consider the implementation of new models of genetic service delivery, utilizing a model that will best serve the needs of their unique patient populations.

Somatic Testing on Gynecological Cancers Improve the Identification of Lynch Syndrome

OBJECTIVE

Recent data from the literature indicate gynecological cancers (GCs) as sentinel cancers for a diagnosis of Lynch syndrome (LS). Clinical approaches to identifying LS have low sensitivity, whereas somatic tests on GCs may be a more sensitive and cost-effective strategy.

METHODS

A series of 78 GCs belonging to 74 patients sent to the Genetic Counselling Service were investigated using microsatellite instability, immunohistochemical expression of mismatch repair (MMR) genes, and MLH1 promoter methylation.

RESULTS

The presence of microsatellite instability was observed in 67.5% of GCs, and the absence of immunohistochemical expression of at least 1 of the 4 MMR proteins was observed in 71.4% of GCs, showing 96.1% concordance between the methods. Methylation analysis using methylation specific multiplex ligation-dependent probe amplification performed on 35 samples revealed MLH1 promoter hypermethylation in 18 cases (54%). Molecular analysis identified 36 LS carriers of MMR variants (27 pathogenetic and 9 variants of uncertain significance), and, interestingly, 3 LS patients had MLH1 methylated GC.With regard to histological features, LS-related GCs included endocervical cancers and also histological types different from the endometrioid cancers. The presence of peritumoral lymphocytes in GCs was statistically associated with LS tumors.

CONCLUSIONS

Somatic analysis is a useful strategy to distinguish sporadic from LS GC. Our data allow the identification of a subset of LS patients otherwise unrecognized on the basis of clinical or family history alone. In addition, our results indicate that some clinicopathological features including age of GC diagnosis; presence of peritumoral lymphocytes; isthmic, endocervical sites, and body mass index value could be useful criteria to select patients for genetic counseling.

Upper tract urothelial carcinomas: frequency of association with mismatch repair protein loss and lynch syndrome

Increased risk for upper tract urothelial carcinoma is described in patients with Lynch syndrome, caused by germline mutations in mismatch repair genes. We aimed to identify the frequency of mismatch repair protein loss in upper tract urothelial carcinoma and its potential for identifying an association with Lynch syndrome. We queried our database to identify upper tract urothelial carcinomas. Patients were cross-referenced for history of colorectal carcinoma or other common Lynch syndrome-associated neoplasms to enrich for potential Lynch syndrome cases. Tumor histopathologic characteristics were reviewed and each case was analyzed for loss of mismatch repair proteins, MLH1, MSH2, MSH6, and PMS2, by immunohistochemistry. Of 444 patients with upper tract urothelial carcinoma, a subset of 215 (encompassing 30 with upper tract urothelial carcinoma and another common Lynch syndrome-associated neoplasm) was analyzed for loss of mismatch repair protein expression. Of 30 patients with Lynch syndrome-associated neoplasms, six had documented Lynch syndrome, including two with Muir-Torre syndrome. Mismatch repair protein loss was identified in 7% of total upper tract urothelial carcinomas and 30% of patients with Lynch syndrome-associated neoplasms (including all patients with Lynch syndrome/Muir-Torre syndrome). Of patients without history of Lynch syndrome-associated neoplasms, 5 of 184 (2.7%) had loss of mismatch repair protein expression. Twelve cases with mismatch repair protein loss demonstrated loss of MSH2 and MSH6, and 2 had isolated loss of MSH6. MLH1 and PMS2 expression were consistently retained. Although increased intratumoral lymphocytes, inverted growth, pushing tumor-stromal interface, and lack of nuclear pleomorphism were more commonly seen in cases with mismatch repair protein loss, only intratumoral lymphocytes and presence of pushing borders were statistically significant. MLH1 and PMS2 testing appear to have little utility in upper tract urothelial carcinoma; however, mismatch repair protein loss of MSH2 and/or MSH6 by immunohistochemistry seems relatively sensitive and specific for identifying patients with potential Lynch syndrome.

Lynch Syndrome Screening in the Gynecologic Tract: Current State of the Art

Lynch syndrome underlies approximately 5% of endometrial cancers and ∼1% of ovarian cancers. Gynecologic malignancies are often the presenting cancer in these patients. Therefore, there is considerable benefit to identifying these patients and enrolling them and affected family members in surveillance programs for secondary malignancies. The molecular basis for Lynch syndrome is a defect in the DNA mismatch repair (MMR) system. Tumors can be screened for these defects using immunohistochemistry to identify loss of MMR proteins or by enlisting polymerase chain reaction to identify the microsatellite instability that attends dysfunctional MMR. However, diagnostic confirmation of Lynch syndrome requires germline mutational testing. The algorithm for screening endometrial carcinomas for Lynch syndrome remains a subject of debate, with some studies supporting universal screening and others proposing a hybrid approach informed by clinicopathologic features. This review discusses the rationales and relative merits of current Lynch syndrome-screening approaches for endometrial and ovarian cancers and provides pathologists with an informed approach to Lynch syndrome testing in gynecologic cancers. It also addresses the clinical difficulties presented by cases with discordant screening and germline results (Lynch-like cancers) and emphasizes the critical role of strong communication with clinician and genetic counseling colleagues to ensure that the significance of a positive screening test is appropriately conveyed to patients. Finally, it discusses the need for more nuanced cost-effective analyses and the potential role for next-generation sequencing panels in future screening efforts.

Clinicopathologic Significance of Mismatch Repair Defects in Endometrial Cancer: An NRG Oncology/Gynecologic Oncology Group Study

PURPOSE

The clinicopathologic significance of mismatch repair (MMR) defects in endometrioid endometrial cancer (EEC) has not been definitively established. We undertook tumor typing to classify MMR defects to determine if MMR status is prognostic or predictive.

METHODS

Primary EECs from NRG/GOG0210 patients were assessed for microsatellite instability (MSI), MLH1 methylation, and MMR protein expression. Each tumor was assigned to one of four MMR classes: normal, epigenetic defect, probable mutation (MMR defect not attributable to MLH1 methylation), or MSI-low. The relationships between MMR classes and clinicopathologic variables were assessed using contingency table tests and Cox proportional hazard models.

RESULTS

A total of 1,024 tumors were assigned to MMR classes. Epigenetic and probable mutations in MMR were significantly associated with higher grade and more frequent lymphovascular space invasion. Epigenetic defects were more common in patients with higher International Federation of Gynecology and Obstetrics stage. Overall, there were no differences in outcomes. Progression-free survival was, however, worse for women whose tumors had epigenetic MMR defects compared with the MMR normal group (hazard ratio, 1.37; P < .05; 95% CI, 1.00 to 1.86). An exploratory analysis of interaction between MMR status and adjuvant therapy showed a trend toward improved progression-free survival for probable MMR mutation cases.

CONCLUSION

MMR defects in EECs are associated with a number of well-established poor prognostic indicators. Women with tumors that had MMR defects were likely to have higher-grade cancers and more frequent lymphovascular space invasion. Surprisingly, outcomes in these patients were similar to patients with MMR normal tumors, suggesting that MMR defects may counteract the effects of negative prognostic factors. Altered immune surveillance of MMR-deficient tumors, and other host/tumor interactions, is likely to determine outcomes for patients with MMR-deficient tumors.

Lynch Syndrome: Female Genital Tract Cancer Diagnosis and Screening

Lynch syndrome is responsible for approximately 5% of endometrial cancers and 1% of ovarian cancers. The molecular basis for Lynch syndrome is a heritable functional deficiency in the DNA mismatch repair system, typically due to a germline mutation. This review discusses the rationales and relative merits of current Lynch syndrome screening tests for endometrial and ovarian cancers and provides pathologists with an informed algorithmic approach to Lynch syndrome testing in gynecologic cancers. Pitfalls in test interpretation and strategies to resolve discordant test results are presented. The potential role for next-generation sequencing panels in future screening efforts is discussed.

Clinicopathologic Comparison of Lynch Syndrome-associated and "Lynch-like" Endometrial Carcinomas Identified on Universal Screening Using Mismatch Repair Protein Immunohistochemistry

Expanded testing for Lynch syndrome (LS) is increasingly recommended for patients with endometrial carcinomas, and immunohistochemistry (IHC) for tumor loss of mismatch-repair (MMR) protein expression is the most common primary screen. This has led to the recognition of MMR-IHC-deficient cases without identifiable mutations on directed germline sequencing. The clinical implications of such "Lynch-like" (LL) cancers are unclear. We here report the clinicopathologic features of putative familial endometrial carcinoma identified on universal MMR-IHC screening with attention to cases with discordant IHC and germline results. The files of the University of Virginia Pathology Department were retrospectively searched for all MMR-deficient endometrial carcinomas identified on screening. Cases were categorized as likely sporadic (MLH1/PMS2 loss, evidence of MLH1 promoter hypermethylation) or putative LS (PLS) (loss of MSH2/MSH6, MSH6, or PMS2). PLS cases were further subdivided into LS and LL groups on the basis of the presence or absence of a confirmatory mutation by germline testing, and the clinicopathologic features of these cases were compared. A deficiency of ≥1 MMR protein was observed in 31.4% (66/210) of endometrial carcinomas, including 26 PLS cases, 15 of which had germline testing. Directed germline sequencing confirmed LS in 46.7% (7/15); the remaining cases were classified as LL. High-grade and/or biphasic morphology was seen in 42.9% (3/7) of LS and 62.5% (5/8) of LL cases; the remaining cases showed low-grade, conventional endometrioid morphology. High level microsatellite instability was observed in 71.4% (5/7) of LL cases. The majority of cases from both groups (LS: 85.7% [6/7]; LL: 87.5% [7/8]) were low-stage (T1a/T1b). Endometrial carcinoma was the presenting malignancy in 85.7% (6/7) of LS patients and 87.5% (7/8) of LL patients. Family history was suggestive of LS in 28.5% (2/7) of LS patients and 12.5% (1/8) of LL patients. Screening algorithms based on age and cancer history would have failed to identify LS patients in 57.1% (4/7) of cases. Although universal MMR-IHC identifies endometrial carcinoma patients with LS who would have been missed using targeted screening algorithms, it also identifies cancers with discordant IHC and germline results for which the somatic versus germline origin of the MMR defect is unclear. Further study of this LL group is required before drawing definitive conclusions about their familial cancer risk.