Lynch综合征的诊治进展和家系管理北大核心CSCD

Lynch综合征（LS）是遗传性结直肠癌中最常见（约占5%）的一类常染色体显性遗传病,错配修复基因的种系突变和微卫星不稳定是其区别于其他遗传性结直肠癌的两大特点。《中国肿瘤临床》2016年第20期＂专家论坛＂栏目特邀浙江大学医学院附属第二医院肿瘤内科副主任袁瑛教授对LS的最初定义、诊断标准和筛查标准的变迁、最新治疗进展和家系管理进行综述,旨在帮助临床医师进一步了解LS.     

Lynch综合征研究进展

摘 要：Lynch综合征（Lynch syndrome,LS）又称遗传性非息肉病性结直肠癌,是最常见的一种遗传性结直肠癌综合征,占结直肠癌的２％～５％。指的是那些具有错配修复（MMR）基因突变导致易患结直肠癌和其他恶性肿瘤的个体。文章就国内外近10年关于MMR基因突变的特点和对LS的诊断和筛选及其应用的进展作一综述。     

云南省7个Lynch综合征家系中致癌基因突变研究

目的 探讨云南省7个Lynch综合征（Lynch syndrome,LS）家系中常见致病基因突变情况。方法 选取昆明医科大学第一附属医院肿瘤科2008年3月—2013年12月收治的7个经过免疫组织化学检测和微卫星不稳定检测确定为MSI-H和dMMR的家系先证者,并且这7个家系都符合AmsterdamⅡ诊断标准。采用目标区域捕获结合高深度测序技术,对家系首发患者的遗传性结直肠癌相关5个基因外显子及其邻近±2 bp内含子区变异进行分析。结果 7个家系（2个白族家系、2个彝族家系、3个汉族家系）中,2个白族家系和2个彝族家系均未发现已知突变位点。结论 Lynch综合征家系致病突变可能存在民族差异。     

Lynch综合征筛查及治疗研究进展

家族遗传性结直肠癌是一类由于基因胚系变异导致的疾病,其中最常见的是Lynch综合征,也被称为遗传性非息肉病性结直肠癌（hereditary nonpolyposis colorectal cancer,HNPCC）。近年来随着对基因组认识的加深,研究显示Lynch综合征临床表型和治疗靶点均有别于散发型结直肠癌。本文将从Lynch综合征筛查策略、类Lynch综合征再定义,以及Lynch综合征免疫治疗和化学预防等方面综述其研究进展。      

基于中国人Lynch综合征临床标准的家族性结直肠癌胚系突变谱多中心研究

  目的  Lynch综合征作为一种常染色体显性遗传的恶性肿瘤综合征,基于肿瘤家族史对患者进行初筛是目前Lynch综合征筛查的主要手段。本研究旨在明确符合中国人Lynch综合征临床标准的结直肠癌患者最终确诊为Lynch综合征的比例,以及二代测序在Lynch综合征临床诊断中的应用。  方法  2017年2月至2019年10月纳入85例就诊于国内7家医院（浙江大学医学院附属第二医院、北京协和医院、江苏省人民医院、北京大学第一医院、辽宁省肿瘤医院、四川大学华西医院和温州市中心医院）无血缘关系的符合中国人Lynch综合征临床标准的结直肠癌患者,利用含61个已报道与遗传性肿瘤相关基因的二代测序平台检测入组先证者的胚系突变。对于检出的临床意义不明的基因变异,通过一代测序、多重荧光PCR毛细管电泳检测肿瘤组织微卫星状态等手段判读该变异的致病意义。  结果  符合中国人Lynch综合征临床标准的结直肠癌患者中,28.2%检测出Lynch综合征关键基因已知致病性或疑似致病性胚系突变,另外15.3%患者携带上述基因的临床意义不明的变异。通过对这些变异进行分析,本研究认为MLH1基因c.2240_2255 delCTGATCTATACAAAGT通读突变为遗传性结直肠癌的致病性突变;然而目前尚缺乏充足证据证明MLH3 基因第2～11号外显子大片段重复与遗传性结直肠癌的发生存在密切联系。  结论  本研究发现同样基于符合中国人Lynch综合征临床标准的结直肠癌患者,与既往利用一代测序的研究报道相比,二代测序并未提高Lynch综合征的确诊率。但是,二代测序会带来大量临床意义不明的突变。需要谨慎对待尚未明确的基因突变检测结果,必要时应该进行更深入的家系研究和更全面的分子检测以明确这些突变的致病意义。      

基于中国人Lynch综合征临床标准的家族性结直肠癌胚系突变谱多中心研究

  目的  Lynch综合征作为一种常染色体显性遗传的恶性肿瘤综合征,基于肿瘤家族史对患者进行初筛是目前Lynch综合征筛查的主要手段。本研究旨在明确符合中国人Lynch综合征临床标准的结直肠癌患者最终确诊为Lynch综合征的比例,以及二代测序在Lynch综合征临床诊断中的应用。  方法  2017年2月至2019年10月纳入85例就诊于国内7家医院（浙江大学医学院附属第二医院、北京协和医院、江苏省人民医院、北京大学第一医院、辽宁省肿瘤医院、四川大学华西医院和温州市中心医院）无血缘关系的符合中国人Lynch综合征临床标准的结直肠癌患者,利用含61个已报道与遗传性肿瘤相关基因的二代测序平台检测入组先证者的胚系突变。对于检出的临床意义不明的基因变异,通过一代测序、多重荧光PCR毛细管电泳检测肿瘤组织微卫星状态等手段判读该变异的致病意义。  结果  符合中国人Lynch综合征临床标准的结直肠癌患者中,28.2%检测出Lynch综合征关键基因已知致病性或疑似致病性胚系突变,另外15.3%患者携带上述基因的临床意义不明的变异。通过对这些变异进行分析,本研究认为MLH1基因c.2240_2255 delCTGATCTATACAAAGT通读突变为遗传性结直肠癌的致病性突变;然而目前尚缺乏充足证据证明MLH3 基因第2～11号外显子大片段重复与遗传性结直肠癌的发生存在密切联系。  结论  本研究发现同样基于符合中国人Lynch综合征临床标准的结直肠癌患者,与既往利用一代测序的研究报道相比,二代测序并未提高Lynch综合征的确诊率。但是,二代测序会带来大量临床意义不明的突变。需要谨慎对待尚未明确的基因突变检测结果,必要时应该进行更深入的家系研究和更全面的分子检测以明确这些突变的致病意义。      

Lynch综合征研究进展

[摘要] Lynch 综合征（Lynch syndrome,LS）是一种常染色体显性遗传病,是由于几种DNA 错配修复（mismatch repair,MMR）基因（MLH1、MSH2、MSH6、PMS2）中的一种出现种系突变,或由于EPCAM基因缺失导致MSH2 表达丢失引起。LS是遗传性结直肠癌（colorectal cancer,CRC）最常见的原因,其特征为患CRC和子宫内膜癌（endometrial cancer,EC）的风险显著增加,且存在发生其他几种恶性肿瘤的风险。对于LS 的诊断,目前几种临床病理学标准（如阿姆斯特丹标准等）已被用于识别存在Lynch 综合征风险的个体。然而,这些标准的敏感性及特异性有限,仍有赖于临床医生对LS的警惕并关注其家族史。伴有MMR基因变异的LS相关肿瘤通常具有微卫星高度不稳定的特征,由于移码突变新抗原的存在,可以激发强大而持久的免疫反应和肿瘤浸润淋巴细胞浸润,所以对于LS患者,免疫检查点抑制剂将会是一种很有前景的治疗方法。由于LS是一种基因遗传病,与DNA错配修复缺陷具有独特关系,对其的充分理解对相关肿瘤的诊断、预防和治疗具有重要的临床意义。     

Lynch综合征相关性子宫内膜癌研究进展

Lynch综合征（Lynch syndrome）又称遗传性非息肉性结直肠癌综合征,是由DNA错配修复（MMR）基因突变引起的一组常染色体显性遗传病。Lynch综合征患者常患有多种原发性肿瘤,女性患者中子宫内膜癌与之最为密切,称为Lynch综合征相关性子宫内膜癌。目前,对Lynch综合征相关性子宫内膜癌无大样本的数据研究,对其筛查及随访缺乏统一策略。为提高对该病的认识与重视,作者对Lynch综合征相关性子宫内膜癌发病机制、临床病理特点、诊断方法、治疗要点及筛查策略等研究进展进行概述。     

遗传性非息肉病性结直肠癌家系分析

目的　探讨遗传性非息肉病性结直肠癌在我国的发病遗传规律以及流行病学特点。方法　自 1999年 1月至 2 0 0 2年 12月 ,对天津市人民医院 (原名天津市滨江医院 )收治的 2 92例结直肠癌患者进行家系调查 ,从中筛选出符合以下标准的遗传性非息肉病性结直肠癌家系 3 8个 ,对家系的肿瘤发生率、肿瘤谱和临床特点等进行了分析和总结。诊断标准使用Amsterdam标准Ⅰ、Amsterdam标准Ⅱ (ICG HNPCC)和日本HNPCC诊断标准。结果　 3 8个遗传性非息肉病性结直肠癌家系中共有 14 5例癌症患者 ,其中男性 76例 ,女性 69例 ,男女比例为 1.1∶1。原发性结直肠癌平均诊断年龄为 ( 5 5 .73± 15 .88)岁 ,在所有 99例结直肠癌中 ,左半结肠癌及直肠癌 2 9例 ,占 2 9.3 % ;右半结肠癌 70例 ,占 70 .7% ,右半结肠癌占有绝对的优势 ;异时性多发性原发结直肠癌患者占大肠癌患者的 13 .1% ( 13 /99) ;HNPCC相关肿瘤共 46例其发生率由高到低前三位是 :子宫内膜癌 9例 ( 19.6% )、乳腺癌 7例 ( 15 .2 % )、肺癌、胃癌各 6例 ( 13 .0 % ) ;在男女性共患癌中 ,除胰腺癌、纵隔癌外 ,男性发生率均高于女性 ;第一代、第二代以及第三代患者的平均诊断年龄有逐渐年轻化的趋势 ,并具有统计学意义。结论　我国遗传性非息肉病性结直肠癌很可能     

34例子宫内膜癌合并结直肠癌双原发癌的临床特征及其与Lynch 综合征关系分析

目的:探讨子宫内膜癌合并结直肠癌双原发癌患者的临床表现、治疗方法及其预后,并分析与Lynch 综合征关系。方法:回顾性分析中国医学科学院肿瘤医院34例子宫内膜癌合并结直肠癌双原发癌患者的临床病理资料。结果:34例患者的中位发病年龄为51.5（39~ 76）岁,64.7%（22/ 34）有肿瘤家族史,子宫内膜样腺癌占79.4%（27/ 34）。 34例中33例双原发癌患者行手术治疗,19例子宫内膜癌、17例结直肠癌术后行放化疗。2 年生存率为84.3% ,5 年生存率为63.1% 。结论:子宫内膜癌合并结直肠癌双原发癌患者多具有肿瘤家族史、发病年龄早、预后与散发型结直肠癌相近,部分患者符合Lynch 综合征。      

Risk of endometrial cancer for women diagnosed with HNPCC‐related colorectal carcinoma

The risk of endometrial cancer (EC) subsequent to a diagnosis of colorectal cancer in women with a germline mutation in a mismatch repair gene [Lynch syndrome or hereditary non‐polyposis colon cancer (HNPCC)] is unknown. We estimated the risk of EC following a diagnosis of colorectal carcinoma (CRC) for women with Lynch syndrome. A retrospective cohort study was performed on women diagnosed with CRC with a germline mutation in a mismatch repair (MMR) gene (Lynch syndrome cases), and women with microsatellite stable (MSS) CRC who were not known to carry a germline mutation (non‐Lynch cases), identified from the Colon Cancer Family Registry. The incidence of EC following CRC was estimated and compared for women with and without Lynch syndrome, using adjusted hazards ratios calculated for time at risk among each group. A total of 112 women with Lynch syndrome and a previous diagnosis of CRC were compared with 908 women without Lynch and with a MSS CRC diagnosis. The estimated 10‐year cumulative risk of EC subsequent to CRC was 23.4% [95% confidence interval (CI): 15–36%] for Lynch syndrome women compared with 1.6% (95% CI: 0.7–3.8%) for non‐Lynch women. After adjusting for ascertainment, age at diagnosis and diagnosis of other cancers, risk of subsequent diagnosis with EC was elevated sixfold in women with Lynch syndrome compared with non‐Lynch women (HR 6.2; 95% CI 2.2–17.3; p = 0.001). Approximately one quarter of women diagnosed with Lynch syndrome‐associated CRC developed EC within 10 years. This supports the sentinel cancer concept and suggests that active and early management is important for these women.     

Fertility and apparent genetic anticipation in Lynch syndrome

Genetic anticipation is the phenomenon in which age of onset of an inherited disorder decreases in successive generations. Inconsistent evidence suggests that this occurs in Lynch syndrome. A possible cause for apparent anticipation is fecundity bias, which occurs if the disease adversely affects fertility. The purpose of this study was to determine the effect of age of diagnosis of colorectal cancer (CRC) on lifetime fertility in Lynch syndrome, and whether this can falsely create the appearance of genetic anticipation. A computer model simulated age of diagnosis of CRC in hypothetical Lynch syndrome carriers and their offspring. The model assumed similar age distribution of CRC across generations (i.e. that there was no true anticipation). Age distribution of CRC diagnosis, and lifetime fertility rates (grouped by age of diagnosis of CRC) were determined from the Australasian Colorectal Cancer Family Registry (ACCFR). Apparent anticipation was calculated by comparing ages of diagnosis of CRC in affected parent–child pairs. A total of 1,088 patients with CRC were identified from the ACCFR. Total lifetime (cohort) fertility was related to age of diagnosis of CRC (correlation coefficient 0.13, P = 0.0001). In the simulation, apparent anticipation was 1.8 ± 0.54 years (P = 0.0044). Observed apparent anticipation in the ACCFR cohort was 4.8 ± 1.73 years (P = 0.0064). There was no difference in apparent anticipation between the simulate d and observed parent–child pairs (P = 0.89). The appearance of genetic anticipation in Lynch syndrome can be falsely created due to changes in fertility.     

What the physician needs to know about Lynch syndrome: an update

The Lynch syndrome (hereditary nonpolyposis colorectal cancer [HNPCC]), is the most common form of hereditary colorectal cancer (CRC), accounting for 2% to 7% of all CRC cases. The next most common hereditary CRC syndrome is familial adenomatous polyposis (FAP), which accounts for less than 1% of all CRC. Lynch syndrome is of crucial clinical importance due to the fact that it predicts the lifetime risk for CRC and a litany of extra-CRC cancers (of the endometrium, ovary, stomach, small bowel, hepatobiliary tract, upper uroepithelial tract, and brain) through assessment of a well-orchestrated family history. A Lynch syndrome diagnosis is almost certain when a mutation in a mismatch repair gene--most commonly MSH2, MLHI, or, to a lesser degree, MSH6--is identified. Once diagnosed, the potential for significant reduction in cancer-related morbidity and mortality through highly targeted surveillance may be profound. Particularly important is colonoscopy initiated at an early age (ie, 25 years) and repeated annually due to accelerated carcinogenesis. In women, endometrial aspiration biopsy and transvaginal ultrasound are important given the extraordinarily high risk for endometrial and ovarian carcinoma. These cancer control strategies have a major impact on at-risk family members once they have been counseled and educated thoroughly about Lynch syndrome's natural history and their own hereditary cancer risk.     

Lynch syndrome: implications for the surgeon

Hereditary nonpolyposis colorectal cancer (HNPCC), or Lynch syndrome, is an autosomal dominant syndrome characterized by onset of colorectal cancer (CRC) at an early age, right-sided predominance, excess synchronous and metachronous colorectal neoplasms, and extracolonic neoplasms. It is the most common of the hereditary CRCs, so the practicing surgeon should expect to encounter patients with this disease. The diagnosis of HNPCC, which begins with a complete family history and a high index of suspicion by the clinician, has important implications in the management and surveillance of not only the affected individual but also for the individual's family. In this article, the diagnosis and management of Lynch syndrome will be reviewed, with emphasis on the implications for the surgeon.     

Evaluating Lynch syndrome in very early onset colorectal cancer probands without apparent polyposis

To characterize the frequency of germline mutations associated with Lynch syndrome and review the potential expanded differential diagnoses in very early onset colorectal cancer (CRC) cases without apparent polyposis. Retrospectively reviewed medical records of 96 probands with CRC diagnosed prior to age 36 from three cancer centers. Determined the frequency of germline mutations in probands meeting different clinical criteria used to identify Lynch syndrome. Three of 46 (6.5%) single case indicators (probands without additional personal or family history suspicious for Lynch syndrome) were identified to carry a deleterious or suspected deleterious mismatch repair (MMR) mutation compared with 10 of 19 (52.6%) in the cases meeting at least one additional revised Bethesda guideline, and 11 of 15 (73.3%) in the cases meeting Amsterdam criteria. Two families without MMR mutations were documented to have a germline APC or TP53 mutation after additional clinical features were identified. Our results suggest that single cases of CRC (those without additional personal or family history suspicious of Lynch syndrome) diagnosed prior to age 36 infrequently have identifiable MMR mutations, especially when compared to cases meeting additional criteria. Careful attention to evolving or additional clinical features is warranted and may lead to an alternate genetic diagnosis in families with early onset CRC.     

Young age and a positive family history of colorectal cancer are complementary selection criteria for the identification of Lynch syndrome

Families at high risk for Lynch syndrome can effectively be recognised by microsatellite instability (MSI) testing. The aim of the present study is to compare the effectiveness of a MSI test for the identification of Lynch syndrome in patients selected by a pathologist mainly based on young age at diagnosis (MSI-testing-indicated-by-a-Pathologist; MIPA), with that of patients selected by a clinical geneticist mainly based on family history (MSI-testing-indicated-by-Family-History; MIFH).Patients with a Lynch syndrome associated tumour were selected using MIPA (n = 362) or MIFH (n = 887). Germline DNA mutation testing was performed in 171 out of 215 patients (80%) with a MSI positive tumour.MSI was tested positive in 20% of the MIPA-group group compared to 16% in the MIFH-group (P = 0.291). In 91 of 171 patients with MSI positive tumours tested for germline mutations were identified as Lynch syndrome patients: 42% in the MIPA-group and 56% in the MIFH-group (P = 0.066). Colorectal cancer (CRC) or endometrial cancer (EC) presenting at an age below 50 years would have led to the diagnosis of Lynch syndrome in 89% of these families (CRC below 50 years: 88% and EC below 50 years: 12%). Families detected by MIPA were characterised more often by extracolonic Lynch syndrome associated malignancies, especially EC (P < 0.001).Our results indicate that recognition of Lynch syndrome by CRC or EC below 50 years is as effective as a positive family history. Families from patients selected by individual criteria more often harbour extracolonic Lynch syndrome associated malignancies.     

Evaluation of yield and experiences of age-related molecular investigation for heritable and nonheritable causes of mismatch repair deficient colorectal cancer to identify Lynch syndrome

Universal mismatch repair deficiency (dMMR) testing of colorectal cancer (CRC) is promoted as routine diagnostics to prescreen for Lynch syndrome. We evaluated the yield and experience of age-related molecular investigation for heritable and nonheritable causes of dMMR in CRC below age 70 to identify Lynch Syndrome. In a prospective cohort of 3602 newly diagnosed CRCs below age 70 from 19 hospitals, dMMR, MLH1 promoter hypermethylation, germline MMR gene and somatic MMR gene testing was assessed in daily practice. Yield was evaluated using data from the Dutch Pathology Registry (PALGA) and two regional genetic centers. Experiences of clinicians were evaluated through questionnaires. Participating clinicians were overwhelmingly positive about the clinical workflow. Pathologists routinely applied dMMR-testing in 84% CRCs and determined 10% was dMMR, largely due to somatic MLH1 hypermethylation (66%). Of those, 69% with dMMR CRC below age 70 without hypermethylation were referred for genetic testing, of which 55% was due to Lynch syndrome (hereditary) and 43% to somatic biallelic pathogenic MMR (nonhereditary). The prevalence of Lynch syndrome was 18% in CRC < 40, 1.7% in CRC age 40-64 and 0.7% in CRC age 65-69. Age 65-69 represents most cases with dMMR, in which dMMR due to somatic causes (13%) is 20 times more prevalent than Lynch syndrome. In conclusion, up to age 65 routine diagnostics of (non-)heritable causes of dMMR CRCs effectively identifies Lynch syndrome and reduces Lynch-like diagnoses. Above age 64, the effort to detect one Lynch syndrome patient in dMMR CRC is high and germline testing rarely needed.     

No evidence of genetic anticipation in a large family with Lynch syndrome

Lynch syndrome is the commonest inherited cause of colorectal cancer (CRC). Genetic anticipation occurs when the age of onset of a disorder decreases in successive generations. It is controversial whether this occurs in Lynch syndrome. Previous studies have included heterogenous groups of subjects from multiple families, including subjects with a clinical diagnosis (based on family history) as well as those with proven germline mismatch repair gene mutations. The purpose of this study was to determine whether genetic anticipation occurs in mismatch repair gene carriers from a single Lynch syndrome family. This study includes members of a single family known to carry an MLH1 gene mutation who are proven germline mutation carriers or obligate carriers (based on their offspring’s mutation status). Evidence of genetic anticipation (determined by age of onset of first CRC) was sought in two ways: Firstly, subjects were grouped as parent-child pairs and individuals were compared with their own offspring; secondly they were grouped by generation within the family tree. The Kaplan–Meier technique was used to adjust for variable follow up times. The family tree consisted of 714 subjects. Ninety-two subjects over five generations were included in the study. There was no evidence of genetic anticipation over the generations. (P = 0.37). Similarly, in the 75 parent–child pairs identified, age of onset of CRC was similar for parents and children (P = 0.51). We could not identify any evidence of genetic anticipation in mutation carriers from a single family with Lynch syndrome.     

Selection of patients with germline <Emphasis Type="Italic">MLH1</Emphasis> mutated Lynch syndrome by determination of <Emphasis Type="Italic">MLH1</Emphasis> methylation and <Emphasis Type="Italic">BRAF</Emphasis> mutation

Lynch syndrome is one of the most common hereditary colorectal cancer (CRC) syndrome and is caused by germline mutations of MLH1, MSH2 and more rarely MSH6, PMS2, MLH3 genes. Whereas the absence of MSH2 protein is predictive of Lynch syndrome, it is not the case for the absence of MLH1 protein. The purpose of this study was to develop a sensitive and cost effective algorithm to select Lynch syndrome cases among patients with MLH1 immunohistochemical silencing. Eleven sporadic CRC and 16 Lynch syndrome cases with MLH1 protein abnormalities were selected. The BRAF c.1799T> A mutation (p.Val600Glu) was analyzed by direct sequencing after PCR amplification of exon 15. Methylation of MLH1 promoter was determined by Methylation-Sensitive Single-Strand Conformation Analysis. In patients with Lynch syndrome, there was no BRAF mutation and only one case showed MLH1 methylation (6%). In sporadic CRC, all cases were MLH1 methylated (100%) and 8 out of 11 cases carried the above BRAF mutation (73%) whereas only 3 cases were BRAF wild type (27%). We propose the following algorithm: (1) no further molecular analysis should be performed for CRC exhibiting MLH1 methylation and BRAF mutation, and these cases should be considered as sporadic CRC; (2) CRC with unmethylated MLH1 and negative for BRAF mutation should be considered as Lynch syndrome; and (3) only a small fraction of CRC with MLH1 promoter methylation but negative for BRAF mutation should be true Lynch syndrome patients. These potentially Lynch syndrome patients should be offered genetic counselling before searching for MLH1 gene mutations.     

Recommendations to improve identification of hereditary and familial colorectal cancer in Europe

Familial colorectal cancer (CRC) accounts for 10–15% of all CRCs. In about 5% of all cases, CRC is associated with a highly penetrant dominant inherited syndrome. The most common inherited form of non-polyposis CRC is the Lynch syndrome which is responsible for about 2–4% of all cases. Surveillance of individuals at high risk for CRC prevents the development of advanced CRC. About 1 million individuals in Western Europe are at risk for Lynch syndrome. We performed a survey to evaluate the strategies currently used to identify individuals at high risk for CRC in 14 Western European countries. Questionnaires were distributed amongst members of a European collaborative group of experts that aims to improve the prognosis of families with hereditary CRC. The survey showed that in all countries obtaining a family history followed by referral to clinical genetics centres of suspected cases was the main strategy to identify familial and hereditary CRC. In five out of seven countries with a (regional or national) CRC population screening program, attention was paid in the program to the detection of familial CRC. In only one country were special campaigns organized to increase the awareness of familial CRC among the general population. In almost all countries, the family history is assessed when a patient visits a general practitioner or hospital. However, the quality of family history taking was felt to be rather poor. Microsatellite instability testing (MSI) or immunohistochemical analysis (IHC) of CRC are usually recommended as tools to select high-risk patients for genetic testing and are performed in most countries in patients suspected of Lynch syndrome. In one country, IHC was recommended in all new cases of CRC. In most countries there are no specific programs on cancer genetics in the teaching curriculum for medical doctors. In conclusion, the outcome of this survey and the discussions within an European expert group may be used to improve the strategies to identify individuals at high risk of CRC. More attention should be given to increasing the awareness of the general population of hereditary CRC. Immunohistochemical analysis or MSI-analysis of all CRCs may be an effective tool for identifying all Lynch syndrome families. The cost-effectiveness of this approach should be further evaluated. All countries with a CRC population screening program should obtain a full family history as part of patient assessment.