Lynch Syndrome Screening of Women with Endometrial Cancer: Feasibility and Outcomes in a Community Program

ObjectiveUniversal screening of endometrial cancer for underlying Lynch syndrome (LS) using DNA mismatch repair immunohistochemistry (MMR IHC) has been recommended. The objective of this study was to assess the feasibility and outcomes of using office endometrial samplings in a community LS screening program.MethodsA community laboratory adopted Cancer Care Ontario's LS screening recommendations. All new endometrial cancers in women aged <70 years were screened for LS using MMR IHC and MLH1 promoter methylation testing cascade for MLH1/PMS2-deficient cases. This retrospective validation study analyzes the first year's results.ResultsOf 693 new endometrial cancers, 467 (67.4%) were eligible for LS screening. Both MMR IHC and MLH1 promoter methylation testing were conclusive in >98% of cases. MMR deficiency (MMRd), which includes LS screen-positive cases, was identified in 25.9% of patients (121/467). LS screen-positive tumours comprised 5.9% (27/467) of all cases.ConclusionEndometrial samplings from community practice are suitable for pre-operative LS screening. This testing can identify MMRd endometrial cancers with significant prognostic implications. Approximately 1 in 20 Ontario women <70 years of age with endometrial cancer screen positive for LS. Pre-operative and/or operative assessment for co-existent colonic neoplasms needs to be considered in this high-risk group. In addition, these women should be referred to genetic counselling.     

Consequences of universal MSI/IHC in screening ENDOMETRIAL cancer patients for lynch syndrome

Objective

Determine factors impacting the uptake of genetic counseling and results of genetic testing following universal tumor testing for Lynch syndrome in patients with endometrial cancer.

Methods

The study population consisted of two unselected cohorts of endometrial cancer patients, 408 identified retrospectively and 206 identified prospectively. Immunohistochemistry for mismatch repair protein expression and/or microsatellite instability analysis was performed on these tumors. MLH1 methylation analysis was performed on tumors with loss of MLH1 protein. Tumor studies were considered suggestive of Lynch Syndrome if they showed immunohistochemical loss of MSH2, MSH6 or PMS2, loss of MLH1 without MLH1 promoter methylation, and/or microsatellite instability. Participants with suggestive tumor studies were contacted and offered genetic counseling and testing.

Results

In the retrospective cohort, 11% had tumor studies suggestive of Lynch syndrome, and 42% was seen for genetic counseling. A germline mutation was detected in 40%, and one had a variant of uncertain significance. In the prospective cohort, 8.7% of patients had tumor testing suggestive of Lynch syndrome; 72% were seen for genetic counseling. Germline mutations were found in 40%, and one had a variant of uncertain significance. Common challenges included timing of re-contact, age, perceived lack of relevance, inability to travel and limited insurance coverage.

Conclusions

There are several barriers to genetic counseling and testing follow-up after universal tumor testing, and uninformative genetic test results present a management challenge. It is important to consider these limitations when implementing an approach to screening endometrial cancer patients for Lynch syndrome.     

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

ObjectiveIn 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.MethodsFrom 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.ResultsIn 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.ConclusionCoverage 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.     

Ovarian cancer linked to Lynch syndrome typically presents as early-onset, non-serous epithelial tumors

Objective

Heredity is a major cause of ovarian cancer and during recent years the contribution from germline mismatch repair (MMR) gene mutations linked to Lynch syndrome has gradually been recognized.

Methods

We characterized clinical features, tumor morphology and mismatch repair defects in all ovarian cancers identified in Swedish and Danish Lynch syndrome families.

Results

In total, 63 epithelial ovarian cancers developed at mean 48 (range 30-79) years of age with 47% being early stage (FIGO stage I). Histologically, endometrioid (35%) and clear cell (17%) tumors were overrepresented. The underlying MMR gene mutations in these families affected MSH2 in 49%, MSH6 in 33% and MLH1 in 17%. Immunohistochemical loss of the corresponding MMR protein was demonstrated in 33/36 (92%) tumors analyzed.

Conclusion

The combined data from our cohorts demonstrate that ovarian cancer associated with Lynch syndrome typically presents at young age as early-stage, non-serous tumors, which implicates that a family history of colorectal and endometrial cancer should be specifically considered in such cases.     

子宫内膜癌中错配修复(MMR)蛋白表达缺失筛查Lynch综合征及其临床病理特点

目的:通过分析比较子宫内膜癌患者的错配修复(MMR)蛋白表达缺失的情况,研究其与临床标准诊断之间的关系,以及MMR蛋白表达缺失者的临床病理特征。方法:收集北京大学第一医院2011年12月至2015年7月收治的313例子宫内膜癌患者的临床资料,免疫组化法分析子宫内膜癌组织中MMR蛋白(MLH1/MSH2/MSH6/PMS2)表达情况。结果:临床诊断或可疑的Lynch综合征22例(7.0%),存在MMR表达缺失者49例(15.7%)。临床诊断或可疑Lynch的患者中,存在MMR表达缺失者的比例明显升高(P=0.011),其中主要是MSH6表达缺失存在差异(P=0.004)。MSH2表达缺失和MSH6表达缺失的患者中合并高血压的比例更低(P=0.002,P=0.045)、淋巴结转移的比例更高(P=0.025,P=0.020)、肿瘤分化差(P=0.030,P=0.010);MSH6表达缺失的患者,相对年龄更小(P=0.021)。结论:免疫组化检测MMR蛋白表达缺失在诊断或可疑Lynch综合征患者中的比例更高,可用于辅助进行Lynch综合征的筛查及诊断。MMR蛋白表达缺失与患者低龄、存在淋巴结转移、肿瘤分化不良等临床病理特征相关。     

Testing for lynch syndrome in people with endometrial cancer using immunohistochemistry and microsatellite instability-based testing strategies – A systematic review of test accuracy

BackgroundLynch syndrome is an inherited genetic condition that is associated with an increased risk of cancer, including endometrial and colorectal cancer. We assessed the test accuracy of immunohistochemistry and microsatellite instability-based testing (with or without MLH1 promoter methylation testing) for Lynch syndrome in women with endometrial cancer.MethodsWe conducted a systematic review of literature published up to August 2019. We searched bibliographic databases, contacted experts and checked reference lists of relevant studies. Two reviewers conducted each stage of the review.ResultsThirteen studies were identified that included approximately 3500 participants. None of the studies was at low risk of bias in all domains. Data could not be pooled due to the small number of heterogeneous studies. Sensitivity ranged from 60.7–100% for immunohistochemistry, 41.7–100% for microsatellite instability-based testing, and 90.5–100% for studies combining immunohistochemistry, microsatellite instability-based testing, and MLH1 promoter methylation testing. Specificity ranged from 60.9–83.3% (excluding 1 study with highly selective inclusion criteria) for immunohistochemistry, 69.2–89.9% for microsatellite instability-based testing, and 72.4–92.3% (excluding 1 study with highly selective inclusion criteria) for testing strategies that included immunohistochemistry, microsatellite instability-based testing, and MLH1 promoter methylation. We found no statistically significant differences in test accuracy estimates (sensitivity, specificity) in head-to-head studies of immunohistochemistry versus microsatellite instability-based testing. Reported test failures were rare.ConclusionsSensitivity of the index tests were generally high, though most studies had much lower specificity. We found no evidence that test accuracy differed between IHC and MSI based strategies. The evidence base is currently small and at high risk of bias.     

Prospective evaluation of molecular screening for Lynch syndrome in patients with endometrial cancer ≤ 70 years

Objective

Lynch syndrome (LS) is a hereditary syndrome that predisposes to multiple malignancies including endometrial cancer (EC). We aimed to evaluate a diagnostic strategy for LS based on routine analysis of microsatellite instability (MSI) and immunohistochemical (IHC) staining for mismatch repair (MMR) proteins in tumour tissue of all newly diagnosed EC patients ≤ 70 years.

Methods

Consecutive EC patients ≤ 70 years were included prospectively in eight Dutch centres. EC specimens were analysed for MSI, IHC of four MMR proteins, MMR gene methylation status and BRAF-mutations. tumours were classified as; 1) likely to be caused by LS, 2) sporadic MSI-H, or 3) microsatellite stable (MSS).

Results

Tumour specimens of 179 patients (median age 61 years, IQR 57-66) were analysed. In our study 92% of included patients were over 50 years of age. Eleven EC patients were found likely to have LS (6%; 95% CI 3-11%), including 1 patient suspected of an MLH1, 2 of an MSH2, 6 of an MSH6 and 2 of a PMS2 gene defect. Germline mutation analyses revealed 7 MMR gene germline mutations. Ten patients likely to have LS (92%) were older than 50 years. In addition, 31 sporadic MSI-H tumours with MLH1 promoter hypermethylation (17%; 95% CI 13-24%) were identified.

Conclusions

Molecular screening for LS in patients with EC diagnosed ≤ 70 years, leads to identification of a profile likely to have LS in 6% of cases. New screening guidelines for LS are needed, including recommendations for EC patients older than 50 years of age.     

An NRG Oncology/GOG study of molecular classification for risk prediction in endometrioid endometrial cancer

Objectives

The purpose of this study was to assess the prognostic significance of a simplified, clinically accessible classification system for endometrioid endometrial cancers combining Lynch syndrome screening and molecular risk stratification.

Universal Testing to Identify Lynch Syndrome Among Women With Newly Diagnosed Endometrial Carcinoma

BackgroundLynch syndrome (LS) is an autosomal dominant cancer syndrome caused by a germline mutation in the mismatch repair (MMR) genes. Protocols based on immunohistochemical expression of MMR proteins in cancer are used to identify patients with LS.MethodsThe universal LS screening protocol of the Tom Baker Cancer Centre (Calgary, AB) of all patients diagnosed between April 1, 2013 and April 1, 2015 with endometrioid carcinoma of the endometrium was audited through a retrospective chart review. LS status and frequency of protocol compliance at each of the key steps were calculated (Canadian Task Force Classification II-2).ResultsThe cohort consisted of 375 patients. MMR immunohistochemical testing was requested for 321 (85.6%). Expression of at least one protein was lost in 86 (26.8%). Twenty-one (6.5%) patients were eligible for genetic counselling because PMS2, MSH2, or MSH6 protein expression was lost in 19, and two patients had a family history of LS. Eleven (91.7%) of 12 (57.1%) who attended had germline testing, and six (54.5%) showed a mutation diagnostic of LS. LS status among the cohort of 375 patients was positive in six (1.6%), negative in 294 (78.4%), and unknown in 75 (20%) because of protocol non-compliance. LS was confirmed in six (2%) of the 321 women who completed the protocol.ConclusionThis is the first audit of a Canadian-based universal LS screening protocol of patients with endometrial cancer. The success of the protocol is endorsed by the 80% compliance and by the 2% prevalence of LS, which is within the published range.     

Mismatch repair protein deficiency in endometriosis: Precursor of endometriosis-associated ovarian cancer in women with lynch syndrome

ObjectiveWe aimed to elucidate the pathogenesis of ovarian cancer through the loss of mismatch repair (MMR) proteins in women with Lynch syndrome (LS) in this report.Case reportTwo women with LS underwent surgery for synchronous endometrial cancer and ovarian cancer. In both cases, immunohistochemical examination showed concomitant MMR protein deficiency in endometrial cancer, ovarian cancer, and contiguous ovarian endometriosis. In Case 1, the macroscopically normal ovary included multiple endometrioses with MSH2 and MSH6 expression, and FIGO grade 1 endometrioid carcinoma and contiguous endometriosis without MSH2 and MSH6 expression. In Case 2, all endometriotic cells contiguous with carcinoma in the lumen of the ovarian cyst showed loss of the expression of MSH2 and MSH6.ConclusionOvarian endometriosis with MMR protein deficiency may progress to endometriosis-associated ovarian cancer in women with LS. Diagnosing endometriosis in women with LS during surveillance is important.     

Lynch Syndrome in patients with clear cell and endometrioid cancers of the ovary

Objective

Patients with Lynch Syndrome are at an increased risk for a variety of malignancies, including ovarian cancer. Ovarian cancers associated with Lynch Syndrome are predominantly clear cell or endometrioid in histology. Lynch Syndrome is characterized by germline mutations in mismatch repair (MMR) genes. The current study aims to assess the prevalence of loss of MMR expression in patients with endometrioid and clear cell ovarian carcinoma.

Methods

A retrospective review identified 90 patients with endometrioid and/or clear cell carcinomas. Slides made from tumor tissue microarray blocks were evaluated using immunohistochemical stains with antibodies against MLH1, PMS2, MSH2, and MSH6. Statistical analysis was performed.

Results

Seven of the 90 cases (7.8%) had loss of MMR expression. The mean age of patients with loss of MMR expression (47 years) was significantly younger than those with retained MMR expression (p = 0.014). Loss of MMR expression was present in 20% of patients under the age of 53 with clear cell or endometrioid cancers. Genetic studies found that 3 of the 5 patients with loss of MMR expression carried mutations consistent with Lynch Syndrome; acquired hypermethylation of MLH1 was noted in one patient. Six of 7 patients (86%) whose tumors lacked MMR expression had synchronous or metachronous primary malignancies, a significantly greater prevalence than those with retained MMR expression (p < 0.001).

Conclusion

Patients under the age of 53 with clear cell or endometrioid ovarian carcinomas are at a clinically significant risk for loss of MMR expression and Lynch Syndrome; routine screening with immunohistochemical staining should be considered.     

The contribution of the hereditary nonpolyposis colorectal cancer syndrome to the development of ovarian cancer

OBJECTIVE: Ovarian cancer has one of the highest fractions of hereditary cases. The hereditary breast and ovarian cancer syndrome, primarily due to mutations in BRCA1 and BRCA2, is the main cause of heredity, but also the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome confers an increased risk of ovarian cancer. In order to clarify the contribution of HNPCC to the development of ovarian cancer, we collected data on family history of cancer and characterized MMR function in a consecutive series of 128 tumors unselected for age at diagnosis and previously characterized for BRCA gene mutations. METHODS: Expression of the MMR proteins MLH1, PMS2, MSH2, and MSH6 was analyzed by immunohistochemistry using tissue microarray sections. Tumors with reduced staining or loss of staining were also analyzed for microsatellite instability (MSI). RESULTS: Loss of MMR protein expression was identified in 3 ovarian cancers, all of which had a MSI-high phenotype. DNA sequence analysis revealed disease-causing germline mutations (deletions of exons 4-6 in MLH1 and a 1-nucleotide deletion in exon 5 of MSH6) in two patients diagnosed at ages 40 and 49 years, both of whom had family histories suggestive of HNPCC. The genetic defect in the third case, which was a 47-year old woman without knowledge about her family history with loss of MLH1/PMS2 expression in the tumor tissue, remains elusive. A family history suggestive of HNPCC was identified in an additional case, but this tumor showed normal, retained MMR protein expression and a microsatellite stable phenotype. CONCLUSIONS: About 2% of ovarian cancer is caused by germline mutations in the MMR-genes, a minor proportion as compared to the contribution of the BRCA-genes (11% in the present series). However, identification of HNPCC patients is important since it allows inclusion of high-risk individuals into control programs aimed at preventing the more frequent colorectal and endometrial cancers. Tumors within the HNPCC-spectrum should therefore be included when recording a family history of cancer among patients diagnosed with ovarian cancer.     

林奇综合征相关子宫内膜癌研究进展

林奇综合征（lynch syndrome,LS）是一种常染色体显性遗传病,既往称为遗传性非息肉病性结直肠癌（hereditary nonpolyposis colorectal cancer,HNPCC）,是由DNA错配修复（mismatch repair,MMR）基因MLH1、MSH2、MSH6和PMS2的胚系突变引起。LS患者有多种癌变倾向、发病低龄化及家族易感性,可同时或异时发生结直肠癌、子宫内膜癌（endometrial cancer,EC）、卵巢癌、胃癌和乳腺癌等,女性患者中EC与之最为密切,目前我国对于LS相关EC（LS-EC）认识尚不足,并未形成完整的诊疗标准或指南。为提高对LS-EC的认识,综述LS-EC的分子机制、临床病理特征、筛查及诊断、临床治疗手段、预防等。     

Synchronous occult cancers of the endometrium and fallopian tube in an MSH2 mutation carrier at time of prophylactic surgery

BackgroundWomen with Lynch syndrome have a 40 to 60% lifetime risk of endometrial cancer and a 10 to 12% lifetime risk of ovarian cancer and may consider prophylactic gynecological surgery as an option for risk reduction.CaseWe report a case of synchronous primary cancers of the endometrium and fallopian tube diagnosed at time of prophylactic surgery in an MSH2 mutation carrier.ConclusionRisk-reducing gynecological surgery in Lynch syndrome must include complete removal of the fallopian tubes in addition to the ovaries and endometrium, followed by careful pathological review. Prospective studies are needed to clarify the incidence of occult primary carcinoma of the fallopian tube among female MMR mutation carriers undergoing prophylactic surgery.     

MMR deficiency is common in high-grade endometrioid carcinomas and is associated with an unfavorable outcome

Objective

To assess the prevalence of MMR deficiency (dMMR) in contemporary reclassified high-grade endometrial carcinomas and correlate dMMR with molecular alterations and patient outcome.

Methods

In this study we evaluated the expression of MLH1, MSH2, PMS2 and MSH6 assessed by two different methods in a series of 102 high-grade endometrial carcinomas. The series was comprised of 64 high-grade endometrioid carcinomas (HGEC), 27 serous (ESC), and 11 clear cell (CCC) carcinomas. Absence of expression in any of the proteins was considered dMMR. dMMR was correlated with clinicopathological parameters using a Chi-square test. Univariate and multivariate survival analysis was performed using Kaplan–Meier and Cox regression analyses.

Results

The overall prevalence of dMMR was 28% (29/102) and was seen in 29/64 (45%) HGEC but not detected in any of the ESC and CCC. Within HGEC, dMMR was associated with loss of ARID1A (p = 0.0099), loss of PTEN (p = 0.044) and wild-type TP53 (p = 0.024) expression. dMMR was associated with increased risk for disease specific death by univariate analysis (p = 0.013) among stage III/IV HGEC but not in multivariate analysis (p = 0.12).

Conclusions

Among high-grade endometrial carcinomas, dMMR is restricted to HGEC and could be used as an adjunct diagnostic tool to refute a diagnosis of ESC. The association with dMMR in HGEC with ARID1A/PTEN alterations, TP53 wild type expression pattern and unfavorable outcome suggests that different oncogenetic pathways within HGEC are present.     

Mismatch repair deficiency in ovarian cancer — Molecular characteristics and clinical implications

DNA mismatch repair (MMR) deficiency is associated with increased risk of developing several types of cancer and is the most common cause of hereditary ovarian cancer after BRCA1 and BRCA2 mutations. While there has been extensive investigation of MMR deficiency in colorectal cancer, MMR in ovarian cancer is relatively under-investigated. This review summarizes the mechanism of MMR, the ways in which MMR deficiency can promote carcinogenesis in general and then assesses the available studies regarding MMR deficiency in ovarian cancers with specific emphasis on implications for disease incidence and therapy. The incidence of germline MMR gene mutations in ovarian cancer is only 2% but other mechanisms of gene inactivation mean that loss of expression of one of the seven main genes (MSH2, MSH3, MSH6, MLH1, MLH3, PMS1 and PMS2) occurs in up to 29% of cases. Both mutational and expression data suggest that MMR deficiency is more common in non-serous ovarian cancer. Some studies suggest an improved survival for patients with MMR deficiency compared to historical controls but these do not account for the preponderance of non-serous tumors. A number of in vitro studies have suggested that MMR deficiency is a cause of platinum resistance. To date this has not been categorically demonstrated in the clinic. Larger studies that account for stage of presentation and immunohistochemical subtype are required to assess the effect of MMR deficiency on survival and chemosensitivity. Investigation of MMR related synthetic lethality in colorectal cancer has identified dihydrofolate reductase, DNA polymerase β and DNA polymerase γ and PTEN-induced putative kinase 1 as synthetic lethal to certain MMR defects by causing accumulation of oxidative DNA damage. These synthetic lethal targets require tested and others should be sought within the context of MMR deficient ovarian cancer in an attempt to provide novel therapeutic strategies for these patients.     

Mismatch repair protein expression in 1049 endometrial carcinomas,associations with body mass index,and other clinicopathologic variables

Objective

Links between obesity, with its attendant estrogen abnormalities, and the endometrial carcinoma (EC) DNA Mismatch Repair Protein (MMR) system have recently been proposed. We investigated relationships between body mass index (BMI) and clinicopathological correlates including MMR expression in a large single institution EC cohort.

Methods

Clinical and pathological databases from 2007 to 2012 were used to identify consecutive hysterectomy specimens with EC. Univariate and multivariate analyses were used to explore relationships between BMI, age, stage, tumor type and immunohistochemical results for MLH1, PMS2, MSH2 and MSH6.

Results

1049 EC were identified. Overall, BMI was higher amongst women with normal MMR (p = 0.002). However, when stratified by age and specific MMR, statistically significant differences localized exclusively to women < 50 years old with loss of MSH2 and/or MSH6 (p = 0.003 and p = 0.005 respectively). Higher BMI correlated with endometrioid FIGO 1 and 2 tumors (p < 0.001) and with stage 1a (p < 0.001). Conversely, MMR abnormalities did not show significant associations with stage (p = 0.302) or histologic grade (p = 0.097).

Conclusions

BMI showed statistically significant associations with MMR expression, tumor grade and stage amongst 1049 consecutive EC. Obesity correlates with lower grade and stage EC. A link between BMI and maintenance of the MMR system is not supported by our data because the only statistically significant association occurred in women < 50 years old with MSH2 and/or MSH6 abnormalities where Lynch syndrome related cases are expected to cluster.     

Association of immunohistochemical profiles with histotypes in endometrial carcinomas

ObjectiveAlthough a large number of endometrial cancer patients are cured with surgery alone, there are significant numbers of patients with more aggressive variants of endometrial carcinoma for whom the prognosis remains poor. We investigated the effects of prevalence, histotypes, and immunohistochemical profiles on prognostic value in a hospital-based population.Materials and methodsA retrospective study of surgically resected primary endometrial carcinoma was included. Immunohistochemical stains were performed on formalin-fixed paraffin-embedded tissue microarray sections for β-Catenin, estrogen receptor (ER), progesterone receptor (PR), HER-2, MLH1, MSH2, MSH6, PMS2, and p53.ResultsLoss of mismatch repair expression was detected in 25.4% of samples (29/114, mean age 57 years) of the tumors. The following loss of expression was observed in patients: MLH1/PMS2 in 16.6% of patients, MSH6 in 7.0% of patients, MLH1 in 0.9% of patients, and MSH6/PMS2/MLH1 in 0.9% of patients. Immunohistochemistry of p53 was analyzed for 111 patients. A total of 13 patients (11.7%, mean age 64 years) had p53-abnormal expression (absent, cytoplasmic or diffuse strong positive patterns), and more than half (9/13, 69.2%) had endometrioid histotype. Abnormalities in p53 were significantly associated with histotype (p = 0.001), advanced tumor stage (p = 0.038), death of disease (p = 0.002), PR percentage (p = 0.002), and HER-2 expression (p = 0.018). Immunohistochemical nuclear localization of β-Catenin was detected in 7.1% of the cohort. The combination of p53 and nuclear β-Catenin expressions was not significantly predictive of disease-free or overall survival.ConclusionThe results of this study are useful for management of endometrial cancer in patients with DNA mismatch repair, abnormal p53 expression, or nuclear localization of β-Catenin.     

Lynch综合征相关子宫内膜癌新进展

子宫内膜癌是女性Lynch综合征患者最常见的肠外肿瘤,与散发性子宫内膜癌不同,该病是常染色体显性遗传病,病因及发病机制是错配修复基因(MLH1、MSH2、MSH6及PMS2)的突变或异常表达。患者发病年龄年轻,病理类型多样,包括子宫内膜样癌、透明细胞癌、浆液性癌、未分化癌或癌肉瘤等。由于该病再次发生肿瘤的风险较高,危害大,因此及时治疗Lynch综合征相关的子宫内膜癌是有效预防该类患者再次发生肿瘤的关键。就Lynch综合征相关子宫内膜癌的病因、发病机制、临床病理特征及诊断、治疗和筛查新进展进行综述。