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Lynch syndrome is known by healthcare providers mainly for patients with colorectal cancer. Awareness of other associated tumors, such as endometrial or ovarian cancer, is low. This study aimed to analyze the prevalence of Lynch syndrome in unselected patients with endometrial or ovarian cancer. In addition, the willingness of patients and family members to undergo germline mutation testing was investigated.The medical records of all patients diagnosed with endometrial or ovarian cancer at the Department of Gynecology and Obsterics, University Hospital Dresden, between 1998 and 2012, were screened for a family history of HNPCC-associated cancer. Telephone interviews were used to screen, inform, and enroll patients in this genetic analysis study. Molecular analysis was performed by prescreening of tumor tissue, followed by germline mutation analysis.Two hundred and eighty-three patients were diagnosed with endometrial cancer, 291 with ovarian cancer, and 14 with both. A positive family history for tumors associated with Lynch syndrome was documented for 61 patients. Two pathogenic mutations in the genes MLH1 and MSH2 in nine genetic analyses had already been detected before. After genetic counseling, only 10 of 31 index patients (32.3 %) consented for mutation analysis. However, no additional pathogenic heterozygous mutations were found.In this retrospective cohort study in unselected patients with endometrial or ovarian cancer, only a small number of patients with suspected Lynch syndrome could be identified. Of those, acceptance of germline analyses was moderate, only. As a result, the rate of identified pathogenic germline mutations was lower than expected. Therefore, we are convinced that more information on cancer risks, options for predictive molecular testing and preventive procedures, needs to be provided to patients and gynecologists.

Background Ganglioneuromatous polyposis (GP) is a very rare disorder which may be associated with other clinical manifestations and syndromes, such as Cowden syndrome, multiple endocrine neoplasia (MEN) type II and neurofibromatosis (NF) 1. The risk for malignant transformation of ganglioneuromas is unknown, and the combination of GP with colon cancer has been only very seldom reported. Methods and results We report the case of a 60-year old male patient with adenocarcinoma, adenomas and lipomas of the colon and multiple gastroduodenal lesions combined with generalised lipomatosis and macrocephaly. Based on the initial endoscopic and histological findings, a (restorative) proctocolectomy was recommended but declined by the patient. Instead, a colectomy was performed. The histological examination revealed an unforeseen GP in addition to the colon cancer. Extensive molecular diagnostics allowed for the differential diagnosis of the causes of the clinical manifestations, and the clinical suspicion of Cowden syndrome could not be confirmed using Sanger Sequencing and MLPA for the analysis of PTEN. Finally, a pathogenic germline mutation in PTEN (heterozygous stop mutation in exon 2: NM_000314 (PTEN):c.138C > A; p.Tyr46*) could be detected by next-generation sequencing (NGS), confirming an unusual presentation of Cowden syndrome with GP. Conclusions Cowden syndrome should be considered in cases of GP with extracolonic manifestation and verified by combined clinical and molecular diagnostics. Because GP may represent a premalignant condition, a surgical-oncological prophylactic procedure should be considered. Based on our experience, we recommend early implementation of Panel NGS rather than classical Sanger sequencing for genetic diagnostics, especially if various diagnoses are considered.

Background The aim of this study was to investigate if immunohistochemical expression and mutational status of KIT and PDGFRA in GISTs are associated with the clinical course and disease-free survival after curative resection of the primary tumor without adjuvant systemic therapy. Methods Paraffin-embedded tumor sections of 95 GISTs were analyzed for KIT and PDGFRA expression by immunohistochemistry. PDGFRA expression was judged using a scoring system subdividing tumors in negative/weak and strong immunoreactivity groups. For mutation analysis, exons 9, 10, 11, 13, and 17 of KIT and exons 10, 12, 14, and 18 of PDGFRA were sequenced. Results Of 95 R0-resected GISTs, 69% showed strong PDGFRA immunoreactivity. Gastric GISTs revealed a significantly higher rate of strong PDGFRA immunoreactivity (P = 0.01) and longer DFS (P = 0.015) than GISTs of the small intestine. KIT mutations were detected in 43 of 63 (68.3%) completely sequenced cases while PDGFRA mutations were identified in 6 cases (10%). In multivariate analysis, neither KIT/PDGFRA expression nor mutational status of KIT or PDGFRA were independent prognostic factors. Only mitotic rate predicted recurrence independently. Conclusion Our data do not support the notion that expression of PDGFRA or mutations in KIT or PDGFRA are independent prognostic factors after curative resection of primary GIST. J. Surg. Oncol. 2011;104:59–65. © 2011 Wiley-Liss, Inc.

Background and objective. Hereditary nonpolyposis colorectal cancer (HNPCC) is the most frequent form of hereditary colorectal cancer. In addition to the high lifetime risk for colorectal cancer in mutation carriers, there is also a remarkably increased risk for endometrial cancer (EC). Methods. In this retrospective study, clinical and molecular approach to the individual decision making as to whether or not to perform a prophylactic hysterectomy in a subset of HNPCC patients is discussed. 147 female patients meeting at least one criterion of the Bethesda guidelines were included in this analysis between 1995 and 2003. After clinical and genetic counseling, patients gave informed written consent and microsatellite analysis, immunohistochemistry and sequencing of the mismatch repair genes MLH1 , MSH2 and MSH6 was performed. Results. 11 of the analyzed patients had a personal history of EC and had undergone previous hysterectomy at ages 26 to 62 years. Prophylactic hysterectomy with oophorectomy was considered in postmenopausal women meeting the Amsterdam criteria and/or carrying a disease causing mismatch repair gene mutation who were operated on because of diagnosed colorectal cancer in our center for hereditary cancer. This procedure was performed in 4 patients. None of them had shown any symptoms of a gynecologic malignancy. Preoperative gynecological examination showed no evidence for EC or ovarian cancer in these patients. Postoperative histological examination showed EC stage T1b N0 M0 in 2 patients. Conclusions. Since the efficiency of gynecological surveillance is uncertain, prophylactic hysterectomy could be an option for a subset of HNPCC patients and mutation carriers.

Mononucleotide repeat sequences are particularly prone to frameshift mutations in tumors with biallelic inactivation of the mismatch repair (MMR) genes MLH1 or MSH2. In these tumors, several genes harboring mononucleotide repeats in their coding region have been proposed as targets involved in tumor progression, among which are also the MMR genes MSH3 and MSH6. We have analyzed the expression of the MSH3 and MSH6 proteins by immunohistochemistry in 31 colorectal carcinomas in which MLH1 was inactivated. Loss of MSH3 expression was identified in 15 tumors (48.5%), whereas all tumors expressed MSH6. Frameshift mutations at coding microsatellites were more frequent in MSH3 (16 of 31) than in MSH6 (3 of 31; Fisher’s exact test, P < 0.001). Frameshift mutations and allelic losses of MSH3 were more frequent in MSH3-negative tumors compared with those with normal expression (22 mutations in 30 alleles versus 8 mutations in 28 alleles; χ2, P = 0.001). Biallelic inactivation was evident or inferred for 60% of MSH3-negative tumors but none of the tumors with normal MSH3 expression. In contrast, we did not identify frameshift mutations in the (A)8 tract of MSH3 in a control group of 18 colorectal carcinomas in which the MMR deficiency was based on the inactivation of MSH2. As it has been suggested that mutations of MSH3 might play a role in tumor progression, we studied the association between MSH3 expression and disease stage assessed by lymph node and distant metastases status. Dukes stages C and D were more frequent in primary tumors with loss of MSH3 expression (9 of 13), compared with tumors with retained expression (1 of 14; Fisher’s exact test, P = 0.001), suggesting that MSH3 abrogation may be a predictor of metastatic disease or even favor tumor cell spread in MLH1-deficient colorectal cancers.

Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme in the folate metabolism, which affects DNA synthesis and methylation. Low enzyme activity may reduce the capacity of DNA methylation, and possibly reduce uracil misincorporation into DNA, which can result in double strand breaks. Both processes may be critical for the oncogenic transformation of human cells. Two common amino acid-changing and enzyme activity-reducing nucleotide polymorphisms (677C→T/Ala222Val and 1298A→C/Glu428Ala) have been described in MTHFR . We performed estimations of the relative risk associated with these two polymorphisms in samples from 287 colorectal cancer patients, compared to 346 healthy controls. Relative risk were further determined for subpopulations of cancer patients having sporadic ( n =227) or suspected/verified hereditary disease ( n =60) and tumours exhibiting high-level microsatellite instability ( n =41) or not ( n =246). No significant differences for the relative risk of colorectal cancer were observed for the MTHFR genotypes either alone or in combination in the analysed cohorts, although the frequency of the 1298AA+AC genotypes was increased among the 60 cases with hereditary disease. Whereas our results do not support an association of high enzyme activity and increased risk of colorectal cancer in general, we can not exclude an association of patients with hereditary disease and the MTHFR 1298A→C variant.

A better understanding of the molecular basis of hereditary colorectal cancer syndromes such as hereditary nonpolyposis colorectal cancer syndrome (HNPCC) and familial adenomatous polyposis (FAP) has profound consequences for both the diagnosis and (prophylactic) treatment of (pre)malignant neoplastic lesions. Sequence analysis of the underlying genes for these conditions and the detection of disease-causing genetic alterations in an index patient enable predictive testing for individuals at risk within an affected family. However, the clinical implications of predictive molecular testing depend on the overall penetrance and variability in the expression of pathogenic mutations. The extent of these parameters differs considerably among the various known hereditary colorectal cancer syndromes. Hence the integration of genetic information into the daily surgical practice remains challenging. This review provides an update on the indications for family assessment, purpose and limitations of the genetic testing and resulting recommendations for prophylactic surgery in FAP and HNPCC.

Die Entwicklung moderner minimal-invasiver Diagnose- und Behandlungsverfahren auf dem Gebiet der kolorektalen Adenome und Karzinome ermöglicht eine effektive Überwachung von Risikopersonen, andererseits erfolgt durch die endoskopische Abtragung oder transanale bzw. TEM-technische Resektion von Adenomen bereits eine erhebliche Karzinomprävention. Die Einführung der laparoskopischen Technik bei der Resektion kolorektaler Tumoren könnte nach Evaluierung der bisherigen Ergebnisse zu einer weiteren Verringerung der Hospitalisierung und operationsassoziierten Morbidität der Patienten bei gleicher Prognose führen. Kennzeichnend für familiäre Formen des kolorektalen Karzinoms ist das hohe Risiko für die Entwicklung kolorektaler Tumoren, jedoch auch für weitere extrakolonische Neoplasien. Dies trifft für das hereditäre Nicht-Polyposis-assoziierte kolorektale Karzinom (HNPCC), die familiäre Polyposis (FAP) und die selteneren Formen wie Peutz-Jeghers-Syndrom und juvenile Polyposis zu. Die Anwendung der molekularen Diagnostik in diesen Familien ermöglicht durch die Identifizierung von Mutationsträgern und Nichtmutationsträgern einerseits die gezielte Eingliederung von Hochrisikopersonen (Mutationsträgern) in spezielle, auf das jeweilige Syndrom zugeschnittene Überwachungs- und Vorsorgeprogramme und erspart andererseits Personen mit durchschnittlichem Risiko (Nichtmutationsträgern) unnötige und teilweise invasive Diagnostik. Bezüglich des chirurgischen Vorgehens bei Patienten mit einer Form des hereditären kolorektalen Karzinoms gibt es bereits etablierte Verfahren, wie die Durchführung einer restaurativen Proktokolektomie bei der FAP, bei anderen Formen, wie bei HNPCC, sind diese noch in der Diskussion. Wesentliche Fortschritte bei der Prävention kolorektaler Tumoren sind in den nächsten Jahren möglicherweise auf dem Gebiet der Chemoprävention zu erwarten. Development of modern, minimally invasive methods for diagnosis and treatment in the field of colorectal tumours enables an effective surveillance for persons at high risk as well as a distinct cancer prevention by endoscopic, transanal or TEM removal of colorectal adenomas. Introduction of laparoscopic techniques in the resection of colorectal tumours could entail, after evaluation of preliminary results, a decreased duration of hospitalisation and procedure-associated morbidity in patients with the same prognosis. The very high risk for development of colorectal tumours as well as for some extracolonic neoplasia is typical for familial colorectal cancer syndromes. This concerns hereditary nonpolyposis colorectal cancer (HNPCC) syndrome, familial polyposis coli, and the infrequent forms like Peutz-Jeghers syndrome and juvenile polyposis. Molecular diagnostics has the power to identify carriers and noncarriers of a mutated gene in these families and therefore may permit clear-cut decisions regarding inclusion in special surveillance programmes, which is recommended for all persons at risk from affected families. Concerning the surgical approach in patients with hereditary colorectal cancer, well-accepted routine procedures like restorative proctocolectomy in familiar polyposis patients have already been established; in other forms like HNPCC the best surgical modality is still under discussion. Remarkable progress in the prevention of colorectal tumours could be expected from chemoprevention trials in the next years. Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Germline mutations in human mismatch repair (MMR) genes yield a predisposition for the hereditary nonpolyposis colon cancer (HNPCC) syndrome. In contrast to hMLH1 and hMSH2, little is known about the overall involvement of hMSH6 in colorectal cancer. We investigated 82 tumors from patients who fulfilled the Bethesda guidelines for HNPCC as well as 146 sporadic tumors, analyzing microsatellite instability and expression of the 4 MMR proteins hMSH6, hMSH2, hMLH1 and hPMS2. Four tumors with lost expression and 1 tumor with cytoplasmic expression of hMSH6 were identified. Sequence analysis revealed germline mutations in 4 of the 5 patients, including 1 patient with sporadic disease. The lost or reduced expression of hMSH2 and hMLH1 was always identical to its heterodimerization partners, hMSH6 and hPMS2, respectively. Furthermore, hMSH2 expression was reduced upon hMSH6 deficiency. Abnormal expression of 1 or more of the 4 proteins was always associated with a high level of microsatellite instability (MSI-H). Conversely, all but 1 of the 44 MSI-H tumors had abnormal expression of 1 or more of the proteins, basically excluding additional genes associated with the MSI-H phenotype. We conclude that the involvement of somatic or epigenetic hMSH6 inactivation in colorectal cancer is rare. © 2001 Wiley-Liss, Inc.

Hereditary Colorectal Carcinomas – Reflection on Preventive Surgery Hereditary Nonpolyposis Colorectal Cancer (HNPCC) accounts for about 5% of all colorectal cancers and is the most frequent familial form; familial adenomatous polyposis coli accounts for about 1%. Prerequisitive for individually tailored surveillance is the identification of the pathogenic germline mutation. In classical FAP, surgical standard is a restorative proctocolectomy while in HNPCC there is no surgical standard other than standard oncological resection due to missing evidence. In HNPCC, prophylactic colectomy before the onset of the first colorectal cancer is not recommended. Main arguments for the extension of the resection in the case of the first colorectal carcinoma in HNPCC are the rate of metachronous colorectal carcinomas of 40–45% in a 10-year interval and rapid tumor progression. In HNPCC, in the case of first colon cancer a subtotal colectomy seems to be indicated. A proctocolectomy or, if indicated, a restorative proctocolectomy may be considered in the case of carcinomas in the lower rectum. These considerations should be evaluated in a prospective clinical trial. Counselling, molecular diagnosis and surgery in patients with hereditary colorectal cancers should only be performed in interdisciplinary centers. Das «Hereditary Nonpolyposis Colorectal Cancer» (HNPCC)-Syndrom bildet mit zirka 5% aller kolorektalen Karzinome die größte Gruppe der familiären Formen; die familiäre adenomatöse Polyposis coli (FAP) macht zirka 1% aus. Voraussetzung für die Indikationsstellung zu individuellen Vorsorgeprogrammen ist die Identifizierung der pathogenen Keimbahnmutation. Bei der klassischen FAP ist die Durchführung einer restaurativen Proktokolektomie die Therapie der Wahl, beim HNPCC-Syndrom gibt es aufgrund fehlender Daten klinischer Studien noch keinen Operationsstandard, der über eine Resektion entsprechend den onkologischen Resektionsprinzipien hinausgeht. Eine prophylaktische Kolektomie vor Manifestation eines kolorektalen Karzinoms bei HNPCC kann bei der gegenwärtigen Datenlage nicht empfohlen werden. Hauptargumente für die Erweiterung des Eingriffs bei manifestem kolorektalem Karzinom bei HNPCC-Patienten sind das Risiko metachroner kolorektaler Karzinome von 40–45% in einem Zeitraum von 10 Jahren und die rasche Tumorprogression. Bei Erstmanifestation eines Kolonkarzinoms erscheint die Durchführung einer subtotalen Kolektomie indiziert. Bei Erstmanifestation des Karzinoms im unteren Rektumdrittel ist die Durchführung einer Proktokolektomie bzw. unter entsprechenden onkologischen und funktionellen Voraussetzungen eine Kolektomie mit Proktomukosektomie und Ileum-Pouch zu erwägen. Die Evaluierung dieser Überlegungen sollte im Rahmen einer prospektiven klinischen Studie erfolgen. Die Beratung, molekulare Diagnostik und chirurgische Therapie von Patienten mit hereditären kolorektalen Karzinomen sollte zunächst nur entsprechenden interdisziplinären Zentren vorbehalten bleiben. Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

To evaluate the involvement of hMSH6 in colorectal cancer, the complete coding sequence and flanking intron regions of the gene were analyzed by DNA sequencing in 10 patients fulfilling Bethesda Guidelines for colorectal tumors and 10 patients with sporadic colorectal carcinoma. In addition, 10 mono- and 10 dinucleotide repeat markers were analyzed for microsatellite instability. A protein-truncating T insertion at codon 218 was identified in the index person of a hereditary non-polyposis colorectal cancer (HNPCC)-like kindred and was accompanied by a somatic T deletion in the tumor. The tumor of this patient was positive for mono- but negative for dinucleotide repeat instability and lacked allelic losses at loci frequently affected in colorectal carcinomas. A novel amino acid change, F340S, was found in a patient with sporadic colon and breast cancer and leukemia but was not detected in 246 chromosomes from healthy anonymous blood donors. In addition, we describe 2 silent and 15 intronic sequence variants not previously reported. Although the frequency is low, we present further evidence for hMSH6 germline mutations that predispose patients to HNPCC-like phenotypes and suggest that mono- and dinucleotide repeat instability testing may be useful for distinguishing between individuals harboring an hMSH2 or hMLH1 mutation and a mutation of the hMSH6 gene.

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant disease with high penetrance, caused by germline mutations in the mismatch repair (MMR) genes MLH1, MSH2, MSH6, PMS2 and MLH3. Most reported pathogenic mutations are point mutations, comprising single base substitutions, small insertions and deletions. In addition, genomic rearrangements, such as large deletions and duplications not detectable by PCR and Sanger sequencing, have been identified in a significant proportion of HNPCC families, which do not carry a pathogenic MMR gene point mutation. To clarify whether genomic rearrangements in MLH1, MSH2 or MSH6 also occur in patients carrying a point mutation, we subjected normal tissue DNA of 137 colorectal cancer (CRC) patients to multiplex ligation-dependent probe amplification (MLPA) analysis. Patients fulfilled the following pre-requisites: all patients met at least one criterion of the Bethesda guidelines and their tumors exhibited high microsatellite instability (MSI-H) and/or showed loss of expression of MLH1, MSH2 or MSH6 proteins. PCR amplification and Sanger sequencing of all exons of at least one MMR gene, whose protein expression had been lost in the tumor tissue, identified 52 index patients without a point mutation (Group 1), 71 index patients with a pathogenic point mutation in MLH1 (n = 38) or MSH2 (n = 22) or MSH6 (n = 11) (Group 2) and 14 patients with an unclassified variant in MLH1 (n =9 ) orMSH2 (n =3 ) orMSH6 (n =2 ) (Group 3). In 13 of 52 patients of group 1 deletions of at least one exon were identified. In addition, in group 3 one EX1_15del in MLH1 was found. No genomic rearrangement was identified in group 2 patients. Genomic rearrangements represent a significant proportion of pathogenic mutations of MMR genes in HNPCC patients. However, genomic rearrangements are rare in patients carrying point mutations in MMR genes. These findings suggest the use of genomic rearrangement tests in addition to Sanger sequencing in HNPCC patients. 2006 Elsevier Ireland Ltd. All rights reserved.

Hereditary nonpolyposis colorectal cancer (HNPCC), clinically defined by the Amsterdam criteria, is associated with mismatch repair gene germline mutations. This study was performed to evaluate the efficiency of combined clinical and molecular diagnostics in identifying carriers of a mutated gene in families meeting criteria of the Bethesda guidelines and to examine the influence of molecular diagnosis on clinical decision-making in carriers and noncarriers. Seventy-two patients meeting criteria of the Bethesda guidelines were tested for microsatellite instabilities (MSI). MSI-H tumors were found in 38 (52.8%) index patients. Complete sequencing of hMLH1 and hMSH2 in 38 MSI-H patients and of hMSH6 in one of these patients revealed 15 pathogenic germline mutations, including three novel mutations, and three novel unclassified germline variants. Twelve of the 15 pathogenic mutations were found in patients fulfilling the Amsterdam I/II criteria. Surgical and genetic counseling was offered to the affected families; as a result of molecular diagnosis in the 15 families, 26 index patients and affected carriers and 8 asymptomatic carriers of a mutated mismatch repair gene were included in the surveillance program, and 26 noncarriers were excluded from this program. Although germline mutations are detected in only 20.8% of patients fulfilling criteria of the Bethesda guidelines, family history and MSI-H tumor classification are both strong indicators for germline mutations in hMSH2, hMLH1, and hMSH6 genes, resulting in a 51.9% mutation detection rate. Identification of individual mutation status allows clear-cut decisions on whether or not inclusion in surveillance programs is indicated.

The aim of this study was to determine whether an intronic germline substitution in the hereditary non-polyposis colorectal cancer (HNPCC) gene hMSH2 represents a genetic risk factor for sporadic CRC. Possible effects of this substitution were investigated by assessment of microsatellite instability and hMSH2 cDNA sequencing. Constitutional DNA from patients with sporadic CRC and healthy controls from the same region in Germany was analysed for the intronic germline T → C transition six bases upstream of exon 13 of hMSH2. 29 of 106 patients (27%) were found to harbour the germline T → C transition as opposed to only 13 of 125 controls (10%; P < 0.001; OR 3.2, CI 1.58–6.63). CRCs from patients with the substitution displayed neither clinical HNPCC-like features nor an increased rate of microsatellite instability. No abnormal cDNA sequence was found at the exon 12–13 border. These data suggest a 3.2-fold increased risk of sporadic CRC for individuals with the intronic hMSH2 transition. However, this substitution might not be pathogenic itself, but may be linked to a locus nearby that is.

205 Background: Small bowel adenocarcinoma (SBA) is an aggressive tumor responsible for poor outcomes with an expected median OS at 5 years inferior to 30%. Because of its low incidence, few prospective studies have been performed leading to insufficient knowledge and absence of standard of care. Aiming to better understand the small bowel carcinogenesis process we screened for somatic mutations a large data set of patients in more than 740 mutational hotspots among 46 genes. Methods: In total, 83 SBA cases were selected from 2 European databases. The sequencing was performed using the Ion 316 Chip. We additionally looked into MSI status and ERBB2 expression (immunochemistry and FISH). Results: Tumors were mostly located in the duodenum (47%) and stage ≥ 3 (63%). Among the 46 genes investigated, 8 were mutated in more than 5% of the cases: KRAS, TP53, APC, SMAD4, PIK3CA, ERBB2, BRAF, and FBXW7. Compelling mutations (7 cases) and amplifications (3 cases) 12% of the patients had an ERBB2 alteration. In this group, ERBB2 alterations were positively associated with dMMR status (p=0.006) and APC mutations (p=0.02) but negatively associated with p53 mutations (p=0.038). Interestingly, ERBB2 mutations were mainly detected within tumors derived from the foregut while ERBB2 amplifications were limited those derived from the midgut. Conclusions: This study describes the first large screening of somatic mutations in SBA using next generation sequencing. ERBB2 mutation was revealed to be one of the most frequent alterations in SBA with a distribution dependent on tumor location. In most cases patients harbored the same p.L755S-ERBB2 mutation. In clinical practice, this study may suggest that more than 10% of the patients with SBA could be treated using anti-ERBB2-targeted agents.[Table: see text]