Cancer risk in Lynch Syndrome

Molecular Biomarkers for the Evaluation of Colorectal Cancer

Objectives: To develop evidence-based guideline recommendations through a systematic review of the literature to establish standard molecular biomarker testing of colorectal cancer (CRC) tissues to guide epidermal growth factor receptor (EGFR) therapies and conventional chemotherapy regimens. Methods: The American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology, and American Society of Clinical Oncology convened an expert panel to develop an evidence-based guideline to establish standard molecular biomarker testing and guide therapies for patients with CRC. A comprehensive literature search that included more than 4,000 articles was conducted. Results: Twenty-one guideline statements were established. Conclusions: Evidence supports mutational testing for EGFR signaling pathway genes, since they provide clinically actionable information as negative predictors of benefit to anti-EGFR monoclonal antibody therapies for targeted therapy of CRC. Mutations in several of the biomarkers have clear prognostic value. Laboratory approaches to operationalize CRC molecular testing are presented.

Molecular Biomarkers for the Evaluation of Colorectal Cancer: Guideline From the American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology, and American Society of Clinical Oncology

OBJECTIVES

To develop evidence-based guideline recommendations through a systematic review of the literature to establish standard molecular biomarker testing of colorectal cancer (CRC) tissues to guide epidermal growth factor receptor (EGFR) therapies and conventional chemotherapy regimens.

METHODS

The American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology, and American Society of Clinical Oncology convened an expert panel to develop an evidence-based guideline to establish standard molecular biomarker testing and guide therapies for patients with CRC. A comprehensive literature search that included more than 4,000 articles was conducted.

RESULTS

Twenty-one guideline statements were established.

CONCLUSIONS

Evidence supports mutational testing for EGFR signaling pathway genes, since they provide clinically actionable information as negative predictors of benefit to anti-EGFR monoclonal antibody therapies for targeted therapy of CRC. Mutations in several of the biomarkers have clear prognostic value. Laboratory approaches to operationalize CRC molecular testing are presented. Key Words: Molecular diagnostics; Gastrointestinal; Histology; Genetics; Oncology.

Mismatch Repair Polymorphisms as Markers of Breast Cancer Prevalence in the Breast Cancer Family Registry

BACKGROUND

Major breast cancer susceptibility genes involved in DNA repair, including BRCA1 and BRCA2, have been identified. However, mutations in these genes account for only 5-10% of identified breast cancer cases. Additional DNA repair pathway genes may also contribute to susceptibility.

MATERIALS AND METHODS

We investigated the association between 12 single nucleotide polymorphisms (SNPs) in mismatch repair (MMR) genes and breast cancer risk among 313 sister-sets enrolled in the New York site of the Breast Cancer Family Registry (BCFR) (n=744) using conditional logistic regression analysis.

RESULTS

An increase in breast cancer risk was observed for women with the MUTYH_rs3219489 variant allele (odds ratio (OR)=2.23, 95% confidence interval (CI)=1.10-4.52) and for women with the MSH2_rs2303428 variant allele (OR=1.73, 95% CI=1.00-2.99).

CONCLUSION

Deficiencies in DNA repair pathways, such as MMR, have implications for the onset of familial breast cancer.

Molecular Biomarkers for the Evaluation of Colorectal Cancer: Guideline From the American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology, and the American Society of Clinical Oncology

Purpose Molecular testing of colorectal cancers (CRCs) to improve patient care and outcomes of targeted and conventional therapies has been the center of many recent studies, including clinical trials. Evidence-based recommendations for the molecular testing of CRC tissues to guide epidermal growth factor receptor (EGFR) -targeted therapies and conventional chemotherapy regimens are warranted in clinical practice. The purpose of this guideline is to develop evidence-based recommendations to help establish standard molecular biomarker testing for CRC through a systematic review of the literature. Methods The American Society for Clinical Pathology (ASCP), College of American Pathologists (CAP), Association for Molecular Pathology (AMP), and the American Society of Clinical Oncology (ASCO) convened an Expert Panel to develop an evidence-based guideline to help establish standard molecular biomarker testing, guide targeted therapies, and advance personalized care for patients with CRC. A comprehensive literature search that included over 4,000 articles was conducted to gather data to inform this guideline. Results Twenty-one guideline statements (eight recommendations, 10 expert consensus opinions and three no recommendations) were established. Recommendations Evidence supports mutational testing for genes in the EGFR signaling pathway, since they provide clinically actionable information as negative predictors of benefit to anti-EGFR monoclonal antibody therapies for targeted therapy of CRC. Mutations in several of the biomarkers have clear prognostic value. Laboratory approaches to operationalize molecular testing for predictive and prognostic molecular biomarkers involve selection of assays, type of specimens to be tested, timing of ordering of tests and turnaround time for testing results. Additional information is available at: www.asco.org/CRC-markers-guideline and www.asco.org/guidelineswiki.

Pathological features and clinical behavior of Lynch syndrome-associated ovarian cancer

OBJECTIVE

Lynch syndrome (LS) is an inherited tumor predisposition condition caused by mutations in the mismatch repair (MMR) genes. Mutation carriers are at increased risk of various malignancies, including ovarian cancer (OC). Relatively little is known about the pathological features and clinical behavior of LS associated OC.

METHODS

We analyzed the data of 1047 proven MMR mutated individuals from a prospectively maintained database at a large referral center for genomic medicine in the North West of England. Data were crosschecked with pathology reports, the National Cancer Registry and death certificates, where appropriate. Data from gynecological surveillance and risk reducing surgery were analyzed.

RESULTS

We identified 53 cases of LSAOC in proven MMR mutated individuals. The cumulative risk of LSAOC was 20% at age 80 in those who retained their ovaries. LSAOC presented at an earlier age (average 51, range 24-70years) than sporadic OC. The predominant histological subtype was endometrioid adenocarcinoma (53%). Most cases presented early (85% at stage I/II vs. 15% at stage III/IV, p<0.001) and overall survival was excellent (80% 5-year survival), however, patients with advanced disease had a poor prognosis (40% 5-year survival). Most women were found to have LS after their OC diagnosis, however, two were detected at Stage 1c through gynecological surveillance and a further three were detected following surgery for screen-detected synchronous endometrial pathology.

CONCLUSION

The predominance of early stage disease in LSAOC is linked to its good prognosis. We support risk-reducing surgery for women whose families are complete especially if undertaking hysterectomy for endometrial risk, and ovarian surveillance as part of gynecological screening for those who have not.

Outcome of 24 years national surveillance in different hereditary colorectal cancer subgroups leading to more individualised surveillance

BACKGROUND

Individuals with hereditary non-polyposis colorectal cancer (HNPCC) have a high risk of colorectal cancer (CRC). The benefits of colonic surveillance in Lynch syndrome and Amsterdam-positive (familial CRC type X familial colorectal cancer type X (FCCTX)) families are clear; only the interval between colonoscopies is debated. The potential benefits for families not fulfilling the Amsterdam criteria are uncertain. The aim of this study was to compare the outcome of colonic surveillance in different hereditary subgroups and to evaluate the surveillance programmes.

METHODS

A prospective, observational study on the outcome of colonic surveillance in different hereditary subgroups based on 24 years of surveillance data from the national Danish HNPCC register.

RESULTS

We analysed 13 444 surveillance sessions, including 8768 incidence sessions and 20 450 years of follow-up. CRC was more incident in the Lynch subgroup (2.0%) than in any other subgroup (0.0-0.4%, p<0.0001), but the incidence of advanced adenoma did not differ between the Lynch (3.6%) and non-Lynch (2.3-3.9%, p=0.28) subgroups. Non-Lynch Amsterdam-positive and Amsterdam-negative families were similar in their CRC (0.1-0.4%, p=0.072), advanced adenoma (2.3-3.3%, p=0.32) and simple adenoma (8.4-9.9%, p=0.43) incidence. In moderate-risk families, no CRC and only one advanced adenoma was found.

CONCLUSIONS

The risk of CRC in Lynch families is considerable, despite biannual surveillance. We suggest less frequent and more individualised surveillance in non-Lynch families. Individuals from families with a strong history of CRC could be offered 5-year surveillance colonoscopies (unless findings at the preceding surveillance session indicate shorter interval) and individuals from moderate-risk families could be handled with the population-based screening programme for CRC after an initial surveillance colonoscopy.

Advances in the recognition and management of hereditary cancer

INTRODUCTION

Constitutional mutations in genes controlling DNA repair, cell-cycle regulation and cell apoptosis can determine an individual's tendency to develop cancer. Hereditary cancer predisposition syndromes present with multiple cancers at a young age and underlie a significant burden of morbidity and mortality. Recent advances in the recognition and management of hereditary cancer will be illustrated with specific examples of developments in diagnosis and treatment.

SOURCES OF DATA

Key recent published literature.

AREAS OF AGREEMENT

The identification of individuals with hereditary cancer offers important opportunities for cancer prevention, early intervention and personalized management.

AREAS OF CONTROVERSY

Individuals at risk of hereditary cancer remain under-recognized. There is a need to develop evidence-based guidelines for the recognition and management of hereditary cancer predisposition conditions.

GROWING POINTS

The study of Mendelian cancer susceptibility syndromes has added to our understanding of hereditary and sporadic cancers and facilitated the development of targeted agents directed against cancer-driving mutations. Increasingly, cancer patients with constitutional gene mutations treated with targeted therapies have improved clinical outcomes.

AREAS FOR TIMELY RESEARCH

Building the infrastructure to enable constitutional gene mutation testing to become integrated into routine cancer care, including the parallel development of robust referral pathways alongside genomic sequencing technologies.

A Detailed Immunohistochemical Analysis of a Large Series of Cervical and Vaginal Gastric-type Adenocarcinomas

Adenocarcinomas exhibiting gastric differentiation represent a recently described and uncommon subtype of non-human papillomavirus (HPV)-related cervical adenocarcinoma. They comprise a spectrum from a well-differentiated variant (adenoma malignum/mucinous variant of minimal deviation adenocarcinoma) to a more poorly differentiated overtly malignant form, generally referred to as gastric-type adenocarcinoma. Rarely, such tumors have also been described as primary vaginal neoplasms. Gastric-type adenocarcinomas exhibit considerable morphologic overlap with adenocarcinomas originating outside the female genital tract, especially mucinous adenocarcinomas arising in the pancreas and biliary tract. Moreover, they often metastasize to unusual sites, such as the ovary and peritoneum/omentum, where they can be mistaken for metastatic adenocarcinomas from other, nongynecologic sites. There is little information regarding the immunophenotype of gastric-type adenocarcinomas, and knowledge of this is important to aid in the distinction from other adenocarcinomas. In this study, we undertook a detailed immunohistochemical analysis of a large series of cervical (n=45) and vaginal (n=2) gastric-type adenocarcinomas. Markers included were cytokeratin (CK)7, CK20, CDX2, carcinoembryonic antigen, CA125, CA19.9, p16, estrogen receptor, progesterone receptor, MUC6, PAX8, PAX2, p53, hepatocyte nuclear factor 1 beta, carbonic anhydrase IX, human epidermal receptor 2 (HER2), and mismatch repair (MMR) proteins. All markers were classified as negative, focal (<50% of tumor cells positive), or diffuse (≥50% tumor cells positive) except for p53 (classified as "wild-type" or "mutation-type"), HER2 (scored using the College of American Pathologists guidelines for gastric carcinomas), and MMR proteins (categorized as retained or lost). There was positive staining with CK7 (47/47-45 diffuse, 2 focal), MUC6 (17/21-6 diffuse, 11 focal), carcinoembryonic antigen (25/31-12 diffuse, 13 focal), carbonic anhydrase IX (20/24-8 diffuse, 12 focal), PAX8 (32/47-20 diffuse, 12 focal), CA125 (36/45-5 diffuse, 31 focal), CA19.9 (11/11-8 diffuse, 3 focal), hepatocyte nuclear factor 1 beta (13/14-12 diffuse, 1 focal), CDX2 (24/47-4 diffuse, 20 focal), CK20 (23/47-6 diffuse, 17 focal), and p16 (18/47-4 diffuse, 14 focal). Most cases were negative with estrogen receptor (29/31), progesterone receptor (10/11), PAX2 (18/19), and HER2 (25/26). p53 showed "wild-type" and "mutation-type" staining in 27 of 46 and 19 of 46 cases, respectively. MMR protein expression was retained in 19 of 20 cases with loss of MSH6 staining in 1 patient with Lynch syndrome. Molecular studies for HPV were undertaken in 2 tumors, which exhibited diffuse "block-type" immunoreactivity with p16, and both were negative. This is the first detailed immunohistochemical study of a large series of gastric-type adenocarcinomas of the lower female genital tract. Our results indicate immunophenotypic overlap with pancreaticobiliary adenocarcinomas but suggest that PAX8 immunoreactivity may be especially useful in distinguishing gastric-type adenocarcinomas from pancreaticobiliary and other nongynecologic adenocarcinomas, which are usually negative. Diffuse "block-type" p16 immunoreactivity in a cervical adenocarcinoma is not necessarily indicative of a high-risk HPV-associated tumor.

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.

A Comprehensive Strategy for Accurate Mutation Detection of the Highly Homologous PMS2

Germline mutations in the DNA mismatch repair gene PMS2 underlie the cancer susceptibility syndrome, Lynch syndrome. However, accurate molecular testing of PMS2 is complicated by a large number of highly homologous sequences. To establish a comprehensive approach for mutation detection of PMS2, we have designed a strategy combining targeted capture next-generation sequencing (NGS), multiplex ligation-dependent probe amplification, and long-range PCR followed by NGS to simultaneously detect point mutations and copy number changes of PMS2. Exonic deletions (E2 to E9, E5 to E9, E8, E10, E14, and E1 to E15), duplications (E11 to E12), and a nonsense mutation, p.S22*, were identified. Traditional multiplex ligation-dependent probe amplification and Sanger sequencing approaches cannot differentiate the origin of the exonic deletions in the 3' region when PMS2 and PMS2CL share identical sequences as a result of gene conversion. Our approach allows unambiguous identification of mutations in the active gene with a straightforward long-range-PCR/NGS method. Breakpoint analysis of multiple samples revealed that recurrent exon 14 deletions are mediated by homologous Alu sequences. Our comprehensive approach provides a reliable tool for accurate molecular analysis of genes containing multiple copies of highly homologous sequences and should improve PMS2 molecular analysis for patients with Lynch syndrome.

Five endometrial cancer risk loci identified through genome-wide association analysis

We conducted a meta-analysis of three endometrial cancer genome-wide association studies (GWAS) and two follow-up phases totaling 7,737 endometrial cancer cases and 37,144 controls of European ancestry. Genome-wide imputation and meta-analysis identified five new risk loci of genome-wide significance at likely regulatory regions on chromosomes 13q22.1 (rs11841589, near KLF5), 6q22.31 (rs13328298, in LOC643623 and near HEY2 and NCOA7), 8q24.21 (rs4733613, telomeric to MYC), 15q15.1 (rs937213, in EIF2AK4, near BMF) and 14q32.33 (rs2498796, in AKT1, near SIVA1). We also found a second independent 8q24.21 signal (rs17232730). Functional studies of the 13q22.1 locus showed that rs9600103 (pairwise r(2) = 0.98 with rs11841589) is located in a region of active chromatin that interacts with the KLF5 promoter region. The rs9600103[T] allele that is protective in endometrial cancer suppressed gene expression in vitro, suggesting that regulation of the expression of KLF5, a gene linked to uterine development, is implicated in tumorigenesis. These findings provide enhanced insight into the genetic and biological basis of endometrial cancer.

Lynch syndrome risk management

Lynch syndrome has been known as hereditary non-polyposis colorectal cancer (HNPCC), and it is a dominantly inherited cancer syndrome caused by genetic mutations in cell mismatch repair genes, often leading to digestive system and female reproductive system tumors. At present, there is a high misdiagnosis rate for Lynch syndrome. This paper reviews the latest progress in Lynch syndrome risk management with regards to its monitoring, surgical treatment, pharmaceutical treatment, life style improvement and screening.

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.

Incidental placenta increta at the time of prophylactic hysterectomy for Lynch syndrome: Insights into individualized decision-making and surgical timing

•Increta in a prophylactic hysterectomy specimen for Lynch syndrome is rare.•Individualizing risk-reducing procedures after childbearing is important.•Shared decision making should include the timing of prophylactic surgery.•Minimizing surgical risks in the postpartum period should be discussed.

Clinical management of patients at inherited risk for gynecologic cancer

PURPOSE OF REVIEW

As more women with an inherited increased risk of gynecologic cancer are identified, the clinician will be challenged to counsel these women on risk-reducing strategies.

RECENT FINDINGS

Although there are some recent studies that show potential for ovarian cancer surveillance strategies, there remains no definitive evidence that surveillance leads to a stage shift or a reduction in mortality. Recent studies support the following conclusions: first, oral contraceptive use reduces ovarian cancer risk without significantly increasing breast cancer risk, second, salpingo-oophorectomy leads to a reduction in ovarian cancer, breast cancer, and overall mortality for women who are carriers of BRCA1 and BRCA2 mutations, and third, the 'ovarian cancers' associated with BRCA mutations actually include fallopian tube and peritoneal cancer and may have a precursor lesion in the fallopian tube; this observation has prompted the provocative suggestion of removing the fallopian tube to reduce ovarian cancer risk.

SUMMARY

Because of the interplay between the hormonal impact of ovarian function on breast cancer risk, the risk reduction associated with oophorectomy, and the impact of early menopause on other health outcomes, an integrated multidisciplinary approach is required to aid in the increasingly complex decisions faced by women with high inherited risk of developing gynecologic cancers.

Total proctocolectomy for rectal cancer in Lynch syndrome: indications and considerations

SUMMARY 

Patients with Lynch syndrome and rectal cancer present a unique clinical challenge. Management of the primary rectal cancer and prophylactic removal of the colon should be considered. In patients requiring a mesorectal excision, a combined prophylactic colon removal can be considered. Although surveillance of the colon with frequent colonoscopies is an alternative, concerns of metachronous colon cancer development support prophylactic removal of the colon as an alternative. Since data are not available to confirm superiority of either approach, the final decision is greatly dependent upon a patient's wishes and preferences. Patients interested in pursuing simultaneous prophylactic colon removal can be offered total proctocolectomy with either ileal pouch anal-anastomosis as a sphincter-preserving alternative or a total proctocolectomy with end ileostomy.

Genetic causes of cancer predisposition in children and adolescents

The acquisition of de novo somatic mutations accounts for approximately 90% of all new cancer diagnoses, while the remaining 10% is due to inherited genetic traits. In this latter category, individuals harbouring germline mutations show a higher likelihood of developing potentially life-threatening cancers, often at a very young age. The study of cancer genetics has profoundly helped our understanding of cancer biology, leading to better characterised malignancies, tailored targeted therapies and the identification of individuals at high risk of cancer diagnosis. This review will discuss examples of cancer syndromes in children, adolescents and young adults, the main underlying gene mutations, and the use of genetic testing to identify gene mutation carriers. Finally, we will describe how gene mutation detection is employed for the life-long management of patients with high susceptibility to cancer, including genetic counselling, increased surveillance, early intervention and use of targeted therapies.

Microsatellite instability use in mismatch repair gene sequence variant classification

Inherited mutations in the DNA mismatch repair genes (MMR) can cause MMR deficiency and increased susceptibility to colorectal and endometrial cancer. Microsatellite instability (MSI) is the defining molecular signature of MMR deficiency. The clinical classification of identified MMR gene sequence variants has a direct impact on the management of patients and their families. For a significant proportion of cases sequence variants of uncertain clinical significance (also known as unclassified variants) are identified, constituting a challenge for genetic counselling and clinical management of families. The effect on protein function of these variants is difficult to interpret. The presence or absence of MSI in tumours can aid in determining the pathogenicity of associated unclassified MMR gene variants. However, there are some considerations that need to be taken into account when using MSI for variant interpretation. The use of MSI and other tumour characteristics in MMR gene sequence variant classification will be explored in this review.

Clinical management of hereditary colorectal cancer syndromes

Hereditary factors are involved in the development of a substantial proportion of all cases of colorectal cancer. Inherited forms of colorectal cancer are usually subdivided into polyposis syndromes characterized by the development of multiple colorectal polyps and nonpolyposis syndromes characterized by the development of few or no polyps. Timely identification of hereditary colorectal cancer syndromes is vital because patient participation in early detection programmes prevents premature death due to cancer. Polyposis syndromes are fairly easy to recognize, but some patients might have characteristics that overlap with other clinically defined syndromes. Comprehensive analysis of the genes known to be associated with polyposis syndromes helps to establish the final diagnosis in these patients. Recognizing Lynch syndrome is more difficult than other polyposis syndromes owing to the absence of pathognomonic features. Most investigators therefore recommend performing systematic molecular analysis of all newly diagnosed colorectal cancer using immunohistochemical methods. The implementation in clinical practice of new high-throughput methods for molecular analysis might further increase the identification of individuals at risk of hereditary colorectal cancer. This Review describes the clinical management of the various hereditary colorectal cancer syndromes and demonstrates the advantage of using a classification based on the underlying gene defects.

Lynch syndrome caused by germline PMS2 mutations: delineating the cancer risk

PURPOSE

The clinical consequences of PMS2 germline mutations are poorly understood compared with other Lynch-associated mismatch repair gene (MMR) mutations. The aim of this European cohort study was to define the cancer risk faced by PMS2 mutation carriers.

METHODS

Data were collected from 98 PMS2 families ascertained from family cancer clinics that included a total of 2,548 family members and 377 proven mutation carriers. To adjust for potential ascertainment bias, a modified segregation analysis model was used to calculate colorectal cancer (CRC) and endometrial cancer (EC) risks. Standardized incidence ratios (SIRs) were calculated to estimate risks for other Lynch syndrome-associated cancers.

RESULTS

The cumulative risk (CR) of CRC for male mutation carriers by age 70 years was 19%. The CR among female carriers was 11% for CRC and 12% for EC. The mean age of CRC development was 52 years, and there was a significant difference in mean age of CRC between the probands (mean, 47 years; range, 26 to 68 years) and other family members with a PMS2 mutation (mean, 58 years; range, 31 to 86 years; P < .001). Significant SIRs were observed for cancers of the small bowel, ovaries, breast, and renal pelvis.

CONCLUSION

CRC and EC risks were found to be markedly lower than those previously reported for the other MMR. However, these risks embody the isolated risk of carrying a PMS2 mutation, and it should be noted that we observed a substantial variation in cancer phenotype within and between families, suggesting the influence of genetic modifiers and lifestyle factors on cancer risks.

The immunohistochemistry signature of mismatch repair (MMR) proteins in a multiethnic Asian cohort with endometrial carcinoma

Endometrial cancer is the most common gynecologic cancer in developed countries and is rising in incidence globally. Although the 5-year survival rates are >80%, factors beyond conventional pathologic features that predict clinical outcomes are still being elucidated. The aims of this study were to define the prevalence and associations of deficient mismatch repair (dMMR) protein expression (MLH1, MSH2, MSH6, PMS2) by immunohistochemistry in a multiethnic Southeast Asian cohort with endometrioid endometrial cancer. A total of 77 patients with adequate formalin-fixed paraffin-embedded specimens were identified. The sections were stained in 2 centers for 4 MMR proteins and examined by 2 independent specialist histopathologists. The mean age for the cohort was 58.6 yr, with 19.4% (15/77) of patients' cancers showing loss of 2 MMR proteins. All 13 cancers with absent MLH1 showed PMS2 loss (13/15), whereas absent MSH2 correlated with MHS6 loss (2/15). There were no significant differences for dMMR cases in age, body mass index, histopathologic characteristics, and clinical outcomes. In dMMR cases, an overrepresentation of patients of Indian ethnic origin was observed compared with Chinese and Malays. These findings suggest that dMMR protein expression in a Southeast Asian endometrial cancer cohort does not correlate with disease outcomes.

Low frequency of HNPCC-associated microsatellite instability and aberrant MMR protein expression in early-onset bladder cancer

OBJECTIVES

Recently, it was shown that patients with Lynch syndrome due to an MSH2 mutation are at increased risk for the development of bladder cancer. To further this discussion, we screened the largest investigated cohort of patients with early-onset bladder cancer for microsatellite instability (MSI) and mismatch repair (MMR) deficiency to determine a possible role of Lynch syndrome in young patients with bladder cancer.

METHODS

A total of 109 cases of bladder tumors from young patients (aged <45 years) were examined for MSI (Bethesda consensus panel). Expression of MMR proteins (hMLH1, hMSH2, and hMSH6) was evaluated by immunohistochemistry using a tissue microarray. Results were compared with a series of unselected consecutive bladder tumors (n = 95).

RESULTS

Regarding the frequency of MSI high (1% vs 0%) or abnormal expression of MMR proteins (2% vs 6.5%), no significant difference between the early-onset and unselected patient group was found.

CONCLUSIONS

In young patients with bladder tumors, MSI and defects in MMR protein expression were not more frequent than in a series of consecutive bladder tumors. Most bladder tumors in young patients are not to be attributed to Lynch syndrome.

Society of Gynecologic Oncology statement on risk assessment for inherited gynecologic cancer predispositions

Women with germline mutations in the cancer susceptibility genes, BRCA1 or BRCA2, associated with Hereditary Breast & Ovarian Cancer syndrome, have up to an 85% lifetime risk of breast cancer and up to a 46% lifetime risk of ovarian, tubal, and peritoneal cancers. Similarly, women with mutations in the DNA mismatch repair genes, MLH1, MSH2, MSH6, or PMS2, associated with the Lynch/Hereditary Non-Polyposis Colorectal Cancer (HNPCC) syndrome, have up to a 40-60% lifetime risk of both endometrial and colorectal cancers as well as a 9-12% lifetime risk of ovarian cancer. Mutations in other genes including TP53, PTEN, and STK11 are responsible for hereditary syndromes associated with gynecologic, breast, and other cancers. Evaluation of the likelihood of a patient having one of these gynecologic cancer predisposition syndromes enables physicians to provide individualized assessments of cancer risk, as well as the opportunity to provide tailored screening and prevention strategies such as surveillance, chemoprevention, and prophylactic surgery that may reduce the morbidity and mortality associated with these syndromes. Evaluation for the presence of a hereditary cancer syndrome is a process that includes assessment of clinical and tumor characteristics, education and counseling conducted by a provider with expertise in cancer genetics, and may include genetic testing after appropriate consent is obtained. This commentary provides guidance on identification of patients who may benefit from assessment for the presence of a hereditary breast and/or gynecologic cancer syndrome.

Performance characteristics of screening strategies for Lynch syndrome in unselected women with newly diagnosed endometrial cancer who have undergone universal germline mutation testing

BACKGROUND

Immunohistochemistry (IHC) for mismatch repair protein expression, microsatellite instability (MSI) testing, tumor morphology, and family history were compared to determine which screening strategy is superior in identifying Lynch syndrome (LS) in unselected women with newly diagnosed endometrial cancer (EC) who have undergone universal germline mutation testing.

METHODS

A prospective cohort study was performed that recruited women with newly diagnosed EC. Participants completed a family history assessment with molecular characterization of EC with IHC and MSI testing and EC assessment for LS-associated morphologic features and underwent universal germline mutation testing for mutations in the mismatch repair pathway. The sensitivity, specificity, and positive and negative predictive values were compared between the screening strategies.

RESULTS

A total of 118 (65%) of 182 consecutive women with EC participated. Of these, 34 women (29%) had tumors that were IHC deficient and 27 women (23%; N = 117) had tumors that were positive for MSI. Twenty women (17%) met IHC criteria and 16 women (15.2%, N = 105) met family history criteria based on Ontario Ministry of Health Criteria for the genetic assessment for LS. Seven women (5.9%) had a germline mutation: 4 had MLH1 (mutL homolog 1), 2 had MSH6 (mutS homolog 6), and 1 had MSH2 (mutS homolog 2). IHC in women aged <60 years had the best performance characteristics, with a sensitivity of 100%, a specificity of 86.1%, a positive predictive value of 58.3%, and a negative predictive value of 100%. Family history and tumor morphology both had the lowest sensitivity at 71.4%. Overall tumor morphology had the poorest performance, with a specificity of 42.1%.

CONCLUSIONS

The mutation rate of 5.9% was higher than expected in this unselected cohort of women with EC. The superior screening strategy to identify women presenting with EC is universal IHC screening in women aged <60 years.

The genetic basis of Lynch syndrome and its implications for clinical practice and risk management

Lynch syndrome is the most common cause of hereditary colon cancer, and accounts for as much as 3% of all colon and endometrial cancers. The identification and management of individuals with Lynch syndrome have evolved over the past 20 years, yet the syndrome remains vastly underdiagnosed. It is important for clinicians to recognize individuals and families who are at risk in order to be able to manage them appropriately and reduce their morbidity and mortality from this condition. This review will touch on the history of Lynch syndrome, the current knowledge of genotype–phenotype correlations, the cancers associated with Lynch syndrome, and management of individuals who are gene carriers.

Pathological stage significantly predicts survival in colorectal cancer patients: a study from two tertiary care centers in India

SUMMARY

Aims: An increase in incidence of early-onset colorectal cancer (EOCRC) in developing countries, including India, is reported recently; however, systematic analyses of clinico-pathological features and disease prognosis has seldom been undertaken. Materials & methods: We studied clinical data pertaining to 1259 colorectal adenocarcinoma patients from two tertiary cancer centers in south India. Results: Approximately 45% of patients were aged below 50 years and poor grade and late-stage tumors were significantly associated with early disease onset. Although tumor grade and stage significantly influenced disease-free survival independently, significant association between survival and age of onset or tumor location was not detected unlike previous observations. Conclusion: Given the sizeable proportion of EOCRC, implementation of the revised Bethesda guidelines may not be tenable in India. More importantly, the previous observation of EOCRC being significantly associated with poor survival could, in part, be due to a higher proportion of advanced-stage tumors.

Knowledge, attitudes and referral patterns of lynch syndrome: a survey of clinicians in australia

This study assessed Australian clinicians’ knowledge, attitudes and referral patterns of patients with suspected Lynch syndrome for genetic services. A total of 144 oncologists, surgeons, gynaecologists, general practitioners and gastroenterologists from the Australian Medical Association and Clinical Oncology Society responded to a web-based survey. Most respondents demonstrated suboptimal knowledge of Lynch syndrome. Male general practitioners who have been practicing for ≥10 years were less likely to offer genetic referral than specialists, and many clinicians did not recognize that immunohistochemistry testing is not a germline test. Half of all general practitioners did not actually refer patients in the past 12 months, and 30% of them did not feel that their role is to identify patients for genetic referral. The majority of clinicians considered everyone to be responsible for making the initial referral to genetic services, but a small preference was given to oncologists (15%) and general practitioners (13%). Patient information brochures, continuing genetic education programs and referral guidelines were favoured as support for practice. Targeted education interventions should be considered to improve referral. An online family history assessment tool with built-in decision support would be helpful in triaging high-risk individuals for pathology analysis and/or genetic assessment in general practice.

Gastric-type adenocarcinoma of the cervix in a patient with Lynch syndrome: A case report

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Lynch syndrome (LS) is an uncommon, genetic disorder which predisposes affected individuals to colorectal, endometrial and ovarian malignancies.

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We report a case of cervical gastric-type adenocarcinoma in a patient with LS.

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Immunohistochemistry for mismatch repair proteins is a useful screening tool in tumours suspected to be associated with LS.

Epithelial-mesenchymal transition in colorectal cancer tissue of patients with Lynch syndrome

AIM

To explore the epithelial-mesenchymal transition (EMT) in tissue from patients with Lynch syndrome, and to interpret biological behaviour of Lynch syndrome.

METHODS

Sixty-eight formalin-fixed and paraffin embedded tissue blocks were analyzed in this study, including tissues from Lynch syndrome (n = 30), sporadic colorectal carcinoma (CRC) (n = 30), and tumor-adjacent tissues (n = 8). Tissue sections were stained for human mutS homolog 2 (hMSH2), human mutL homolog 1 (hMLH1), transforming growth factor-β type II receptor (TGFβRII), E-cadherin, β-catenin, matrix metalloproteinase-7 (MMP-7) and tissue inhibitor of metalloproteinase-2 (TIMP-2) by immunohistochemical staining. Furthermore, clinical data such as age, gender and tumor-node-metastasis stage were also collected retrospectively.

RESULTS

The positive expression rates of hMSH2, hMLH1, TGFβRII, E-cadherin, β-catenin, MMP-7 and TIMP-2 were significantly related to the depth of invasion and lymph node metastasis, but not to sex or tumour size or location. The differences in the positive expression rates of hMSH2, hMLH1, TGFβRII, E-cadherin, cytomembrane β-catenin, cytoplasmic β-catenin, MMP-7 and TIMP-2 were significant between sporadic CRC and Lynch syndrome. The expression of hMSH2 had a positive correlation with that of hMLH1 in Lynch syndrome and sporadic CRC. The expression of TGFβRII had a positive correlation with that of hMSH2, hMLH1 and MMP-7, and a negative correlation with that of TIMP-2. The expression of MMP-7 had a negative correlation with that of TIMP-2 in Lynch syndrome and sporadic CRC. The expression of E-cadherin was positively correlated with that of cytomembrane β-catenin. However, the expression of cytomembrane β-catenin was negatively correlated with that of cytoplasmic β-catenin, and the expression of cytoplasmic β-catenin was positively correlated with that of MMP-7.

CONCLUSION

EMT may play an important role in the development and progression of Lynch syndrome. Lynch syndrome was caused by the mutations of mismatch repair genes, mainly hMSH2 and hMLH1, which also beget the mutational inactivation of TGFβRII. Therefore, the colorectal cancer of Lynch syndrome can escape the inhibitory effect of TGFβ1. However, TGFβ1 can up-regulate the expression of MMP-7 and down-regulate the expression of TIMP-2 in tumors by disassembling the E-cadherin/β-catenin complex in the cytomembrane.

Prevalence of Lynch syndrome among patients with newly diagnosed endometrial cancers

BACKGROUND

Lynch syndrome (LS) is a hereditary condition that increases the risk for endometrial and other cancers. The identification of endometrial cancer (EC) patients with LS has the potential to influence life-saving interventions. We aimed to study the prevalence of LS among EC patients in our population.

METHODS

Universal screening for LS was applied for a consecutive series EC. Tumor testing using microsatellite instability (MSI), immunohistochemistry (IHC) for mismatch-repair (MMR) protein expression and MLH1-methylation analysis, when required, was used to select LS-suspicious cases. Sequencing of corresponding MMR genes was performed.

RESULTS

One hundred and seventy-three EC (average age, 63 years) were screened. Sixty-one patients (35%) had abnormal IHC or MSI results. After MLH1 methylation analysis, 27 cases were considered suspicious of LS. From these, 22 were contacted and referred for genetic counseling. Nineteen pursued genetic testing and eight were diagnosed of LS. Mutations were more frequent in younger patients (<50 yrs). Three cases had either intact IHC or MSS and reinforce the need of implement the EC screening with both techniques.

CONCLUSION

The prevalence of LS among EC patients was 4.6% (8/173); with a predictive frequency of 6.6% in the Spanish population. Universal screening of EC for LS is recommended.

Lynch syndrome presenting as endometrial cancer

BACKGROUND

Lynch syndrome (LS) is the most common form of the hereditary colon cancer syndromes. Because of its high prevalence, a nationwide campaign has begun to screen all colorectal cancers for the genetic abnormalities associated with LS.

CONTENT

Next to colorectal cancer, endometrial cancer is the most common form of malignancy found in women with LS. Identifying individuals who harbor the well-characterized mismatch-repair gene mutations via immunohistochemistry, microsatellite instability analysis, or direct gene sequencing is critical to managing the LS patient and to surveillance for the development of other associated tumor types.

SUMMARY

Although many institutions have begun screening all colorectal tumors for LS, the evidence is sufficient to warrant the testing of all endometrial cancers for LS as well. Various testing algorithms, along with genetic-counseling efforts, can lead to a cost-efficient and beneficial screening program.

Tissue identity testing of cancer by short tandem repeat polymorphism: pitfalls of interpretation in the presence of microsatellite instability

Tissue identity testing by short tandem repeat (STR) polymorphism offers discriminating power in resolving tissue mix-up or contamination. However, one caveat is the presence of microsatellite unstable tumors, in which genetic alterations may drastically change the STR wild-type polymorphism leading to unexpected allelic discordance. We examined how tissue identity testing results can be altered by the presence of microsatellite instability (MSI). Eleven cases of MSI-unstable (9 intestinal and 2 endometrial adenocarcinomas) and 10 cases of MSI-stable tumors (all colorectal adenocarcinomas) were included. All had been previously tested by polymerase chain reaction testing at 5 National Cancer Institute (NCI) recommended MSI loci and/or immunohistochemistry for DNA mismatch repair proteins (MLH1, MSH2, MSH6, and PMS2). Tissue identity testing targeting 15 STR loci was performed using AmpF/STR Identifiler Amplification. Ten of 11 MSI-unstable tumors demonstrated novel alleles at 5 to 12 STR loci per case and frequently with 3 or more allelic peaks. However, all affected loci showed identifiable germline allele(s) in MSI-high tumors. A wild-type allelic profile was seen in 7 of 10 MSI-stable tumors. In the remaining 3 cases, isolated novel alleles were present at a unique single locus in addition to germline alleles. Loss of heterozygosity was observed frequently in both MSI-stable (6/11 cases) and MSI-unstable tumors (8/10 cases). In conclusion, MSI may significantly alter the wild-type allelic polymorphism, leading to potential interpretation errors of STR genotyping. Careful examination of the STR allelic pattern, high index of suspicion, and follow-up MSI testing are crucial to avoid erroneous conclusions and subsequent clinical and legal consequences.

Clinical significance of microsatellite instability in colorectal cancer

INTRODUCTION

Colorectal cancer is a heterogeneous tumor type with regard to molecular pathogenesis and genetic instability. The majority of colorectal cancers display chromosomal instability and follow the classical adenoma-carcinoma sequence of tumor progression. A subset of about 15 % of colorectal cancers, however, displays DNA mismatch repair (MMR) deficiency and the high-level microsatellite instability (MSI-H) phenotype. MSI-H colorectal cancers can occur as sporadic tumors or in the context of hereditary non-polyposis colorectal cancer (HNPCC) or Lynch syndrome.

CLINICAL RELEVANCE

The MSI-H phenotype is a hallmark of Lynch syndrome-associated cancers, which is of diagnostic relevance for the identification of Lynch syndrome mutation carriers. MSI-H colorectal cancers are characterized by a distinct clinical behavior, which results from their particular molecular pathogenesis and gives microsatellite instability testing its clinical significance. The MSI-H phenotype shows association with proximal tumor localization, a dense local lymphocyte infiltration, and a low frequency of distant organ metastasis. Moreover, MSI-H colorectal cancers have a better prognosis than their microsatellite-stable counterparts. A distinct responsiveness of MSI-H colorectal cancer patients towards chemotherapy has been shown in several studies.

CONCLUSIONS

The clinical characteristics of MSI-H cancers are closely linked to their molecular pathogenesis, and research on the molecular alteration characteristic of MSI-H cancers may provide the basis for novel diagnostic or therapeutic approaches.

IMPACT Study: Targeted Prostate Cancer Screening

This letter to the editor clarifies the difference between two similarly named studies and expands on the progress of one—the Identification of Men with a Genetic Predisposition to Prostate Cancer study (IMPACT): Targeted screening in BRCA1/2 mutation carriers and controls.