Review article: The Lynch syndrome (hereditary nonpolyposis colorectal cancer)

Environmental and Genetic Risk Factors for Gastric Cancer

Gastric cancer is a heterogeneous and prevalent disease. The traditional environmental exposures associated with elevated risk of gastric cancer are less prevalent in the USA today. Genetic risks and risks associated with inflammation remain. Most cases are sporadic, and familial clustering is observed in about 10% of the cases. Hereditary gastric cancer accounts for a very low percentage of cases. Here we review the genetic and environmental risk factors associated with the disease. In addition, we will review screening guidelines and current modalities that are available for screening in high-risk populations.

Young-onset colorectal cancer

In the past decades the incidence of colorectal cancer (CRC) in people under the age of 50 years has increased, which is referred to as early-onset CRC or young-onset CRC (YO-CRC). YO-CRC is expected to account for 11% of colon cancers and 23% of rectal cancers by 2030. This trend is observed in different parts of the world and in both men and women. In 20% of patients with YO-CRC, a hereditary cancer syndrome is found as the underlying cause; however, in the majority of patients no genetic predisposition is present. Beginning in the 1950s, major changes in lifestyle such as antibiotic use, low physical activity and obesity have affected the gut microbiome and may be an important factor in YO-CRC development. Owing to a lack of screening, patients with YO-CRC are often diagnosed with advanced-stage disease. Long-term treatment-related complications should be taken into account in these younger patients, making the more traditional sequential approaches of drug therapy not always the most appropriate option. To better understand the underlying mechanism and define relationships between environmental factors and YO-CRC development, long-term prospective studies are needed with lifestyle data collected from childhood.

Lynch syndrome-associated chordoma with high tumor mutational burden and significant response to immune checkpoint inhibitors

Chordoma is a rare malignant bone tumor arising from notochordal tissue. Conventional treatments, such as radical resection and high-dose irradiation, frequently fail to control the tumor, resulting in recurrence and re-growth. In this study, genetic analysis of the tumor in a 72-year-old male patient with refractory conventional chordoma of the skull base revealed a high tumor mutational burden (TMB) and mutations in the MSH6 and MLH1 genes, which are found in Lynch syndrome. The patient and his family had a dense cancer history, and subsequent germline genetic testing revealed Lynch syndrome. This is the first report of a chordoma that has been genetically proven to be Lynch syndrome. Chordomas usually have low TMB; however, this is an unusual case, because the TMB was high, and immune checkpoint inhibitors effectively controlled the tumor. This case provides a basis for determining the indications for immunotherapy of chordoma based on the genetic analysis. Therefore, further extensive genetic analysis in the future will help to stratify the treatment of chordoma.

Environmental and genetic risk factors for gastric cancer

Gastric cancer is a heterogeneous and prevalent disease. The traditional environmental exposures associated with an elevated risk of gastric cancer are less prevalent in the United States today. Genetic risks and risks associated with inflammation remain. Most cases are sporadic and familial clustering is observed in about 10% of the cases. Hereditary gastric cancer accounts for a very low percentage of cases. Here we review the genetic and environmental risk factors associated with the disease.

Neutrophils and micronuclei: An emerging link between genomic instability and cancer-driven inflammation

Two recent studies by Bui and Butin-Israeli et al. have established the novel contribution of neutrophils to genomic instability induction and aberrant shaping of the DNA repair landscape, particularly observed in patients with inflammatory bowel diseases (IBD) and/or progressive colorectal cancer (CRC). In addition, these back-to-back studies uncovered a sharp increase in the numbers of micronuclei and lagging chromosomes in pre-cancerous and cancerous epithelium in response to prolonged PMN exposure. Given the emerging link between neutrophils and micronuclei as well as the established role of micronuclei in cGAS/STING activation, this special commentary aims to elaborate on the mechanisms by which CRC cells may adapt to neutrophil-driven genomic instability while concurrently sustain an inflamed tumor niche. We postulate that such tumor microenvironment with constant immune cell presence, inflammatory milieu, and cumulative DNA damage can drive tumor adaptation and resistance to therapeutic interventions. Finally, we discuss potential novel therapeutic approaches that can be leveraged to target this emerging neutrophil-micronuclei pathological axis, thereby preventing perpetual CRC inflammation and unwanted tumor adaptation.

HFE variants in colorectal cancer and their clinicopathological correlations

The study aimed to screen mutation of human homeostatic iron regulator (HFE) in colorectal carcinoma (CRC) and detect their associations with clinicopathological parameters. Expression of HFE was determined by quantitative polymerase chain reaction in matched CRC and non neoplastic colorectal mucosal tissue of 76 patients. Genomic DNA extracted were subjected to high high-resolution melt curve analysis and Sanger sequencing to detect mutations in HFE. The associations of the identified mutations with a variety of clinical features were determined. Approximately 60% of CRC showed low HFE expression. Of the ten 10 mutations identified in exons 2 and 4, c.187C>G (H63D), c845G>A (C282Y), c.193A>T (S65C), g.3828T>C, g.5795T>C, and g.5728G>A were known mutations. Four novel mutations were discovered; : c.184G>A, c.220T>G, c.322A>C, and c.324T>C. Heterozygous H63D and C282Y mutations were seen in 71% and 49% of cancer tissue, respectively. Tumour site (p = 0.048) and gender (p = 0.039) were significantly associated with H63D and C282Y mutation status, respectively. Local spread of cancer was significantly associated with C282Y mutations in CRC cancer and adjacent non-neoplastic tissue (p = 0.029 & and p = 0.004, respectively). There was a statistically significant association between H63D and C282Y negativity in matched non-neoplastic colorectal mucosa tissue and pathological staging of cancer (p = 0.047 & and p = 0.001, respectively). Patients with H63D and C282Y mutations in cancer tissue tend to have higher survival rates. Hence HFE mutations are common in CRC and are associated with clinicopathological parameters, implying the potential clinical significance of HFE mutations in colorectal carcinogenesis.

Genetic testing for inherited colorectal cancer and polyposis, 2021 revision: a technical standard of the American College of Medical Genetics and Genomics (ACMG)

Colorectal cancer (CRC) is the fourth most frequently diagnosed cancer and 30% of all cases of CRC are believed to have a familial component and up to one-third of these (10%) are hereditary. Pathogenic germline variants in multiple genes have been associated with predisposition to hereditary CRC or polyposis. Lynch syndrome (LS) is the most common hereditary CRC syndrome, caused by variants in the mismatch repair (MMR) genes MLH1, MSH2, MSH6, and PMS2 and is inherited in a dominant manner. Heritable conditions associated with colonic polyposis include familial adenomatous polyposis (FAP) associated with APC pathogenic variants, MUTYH-associated polyposis (MAP) caused by biallelic MUTYH pathogenic variants, and polymerase proofreading-associated polyposis (PPAP) caused by POLE or POLD1 pathogenic variants. Given the overlapping phenotypes of the cancer syndromes along with the limited sensitivity of using clinical criteria alone, a multigene panel testing approach to diagnose these conditions using next-generation sequencing (NGS) is effective and efficient. This technical standard is not recommended for use in the clinic for patient evaluation. Please refer to National Comprehensive Cancer Network (NCCN) clinical practice guidelines to determine an appropriate testing strategy and guide medical screening and management. This 2021 edition of the American College of Medical Genetics and Genomics (ACMG) technical standard supersedes the 2013 edition on this topic.

Universal tumor screening for lynch syndrome: perspectives of patients regarding willingness and informed consent

Aim: Lynch Syndrome is associated with a significant risk of colorectal carcinoma (CRC) and other cancers. Universal tumor screening is a strategy to identify high-risk individuals by testing all CRC tumors for molecular features suggestive of Lynch Syndrome. Patient interest in screening and preferences for consent have been underexplored. Methods: A postal survey was administered to CRC patients in a Canadian province. Results: Most patients (81.4%) were willing to have tumors tested if universal tumor screening were available and were willing to discuss test results with family members and healthcare professionals. The majority (62.6%) preferred informed consent be obtained prior to screening. Conclusion: Patients were supportive of universal screening. They expected consent to be obtained, contrary to current practice across Canada and elsewhere.

The impact of TP53BP1 and MLH1 on metastatic capability in cases of locally advanced prostate cancer and their usefulness in clinical practice

BACKGROUND

Lymph node (LN) metastases increase the risk of death from prostate cancer (CaP). The dysfunction of factors responsible for DNA injury detection may promote the evolution of localized primary tumors into the metastatic form.

METHODS

In this study, 52 cases of CaP were analyzed. The cases were divided into groups of CaP without metastases (N0), with metastases to the LNs (N+), and metastatic LN tissue. Immunohistochemical examinations were performed with antibodies against MDC1, TP53BP1, MLH1, MSH2, MSH6, and PMS2.

RESULTS

Statistical analysis showed lower nuclear expression of TP53BP1 in N+ cases than in N0 cases (P = 0.026). Nuclear TP53BP1 expression was lower in LN cases than in N+ cases (P = 0.019). Statistical analysis showed lower nuclear expression of MLH1 in N+ cases than in to N0 cases (P = 0.003).

CONCLUSION

Decreased expression of both MLH1 and TP53B1 were demonstrated in N+ cases of CaP. This observation could help to determine the risk of nodal metastasis, and to select appropriate treatment modalities for patients with locally advanced CaP.

Back-to-Back Comparison of Colonoscopy With Virtual Chromoendoscopy Using a Third-Generation Narrow-Band Imaging System to Chromoendoscopy With Indigo Carmine in Patients With Lynch Syndrome

INTRODUCTION

Colonoscopic screening with indigo carmine chromoendoscopy (ICC) in patients with Lynch syndrome (LS) improves the adenoma detection rate but is time consuming and poorly used in clinical practice. Narrow-band imaging (NBI), a virtual chromoendoscopy technique, highlights superficial mucosal vessels and improves adenoma characterization. We conducted a prospective multicenter trial in a back-to-back fashion to compare the third-generation NBI with ICC for detecting colonic adenomas in patients with LS.

METHODS

In a multicenter, prospective, noninferiority trial, 138 patients underwent a double colonoscopy, first with NBI, followed by ICC, in a back-to-back design. The primary noninferiority outcome measure was the number of patients with at least one adenoma after NBI compared with the number of patients with at least one adenoma after NBI and ICC.

RESULTS

The 138 analyzable patients were all proven mismatch repair mutation carriers for LS (MLH1 = 33%, MSH2 = 47%, MSH6 = 15%, PMS2 = 4%, and EPCAM = 1%). The mean age (SD) was 40.5 (14.7) years, and 64 (46.4%) were men. The median withdrawal time for an NBI procedure was 8 minutes (interquartile range 6-11) compared with 13 minutes (interquartile range 8-17) for ICC. At least one adenoma was detected during the initial NBI pass in 28 patients (20.3%), and 42 patients (30.4%) had at least one adenoma detected after both NBI and ICC (difference, 10.1%; 95% confidence interval, -0.1%-20.3%); this represents an increase of 50.0% of the adenoma detection rate. ICC detected additional adenomas in 25 patients (18.1%).

DISCUSSION

Colonoscopy combining NBI and ICC detects more adenomas than third-generation NBI alone in patients with LS, respectively, 30.4% vs 20.3% (difference, 10.1%; 95% confidence interval, -0.1 to 20.3), thus failing the noninferiority assumption of NBI compared with combined NBI and ICC. Although less time consuming, colonoscopy using the third-generation NBI cannot be recommended to replace ICC in patients with LS.

Update on the role of chromoendoscopy in colonoscopic surveillance of patients with Lynch syndrome

(Virtual) chromoendoscopy (CE) improves the detection of small or flat colorectal polyps; however, the evidence in high-risk groups, such as patients of Lynch syndrome (LS), is low. Our aim was to identify and update the evidence for the recommendations regarding surveillance of LS patients, for which the current underlying evidence for use of (virtual) CE was explored. A systematic literature search in PubMed, EMBASE, and Cochrane library was conducted, for all studies comparing (virtual) CE with white-light endoscopy in LS patients. Studies are explained in detail, with special attention to study design, type of (virtual) CE, and timing of polypectomy. Eight studies (409 patients) were included. Five were nonrandomized back-to-back studies and three were randomized back-to-back studies (one parallel and two cross-over design). In six studies the polyps were directly removed, while in two studies polyps were removed only during the second caecal withdrawal. Five studies researched CE with indigo carmine and three studies investigated virtual CE. Due to the heterogeneity between studies, no statistical analysis could be performed. There was a large variety in study design, timing of polypectomy, different (virtual) CE techniques and the patients that were included. Based on current literature, no firm conclusions can be drawn with respect to the additional value of (virtual) CE in the surveillance of patients with LS. However, training of endoscopists in detection and removal of nonpolypoid colorectal neoplasms is crucial, as well as stricter adherence to LS surveillance guidelines in daily clinical practice. For future research, standardization in study designs is needed.

Consequences of testing for mismatch repair deficiency of colorectal cancer in clinical practice

INTRODUCTION

Mismatch repair deficiency (dMMR) can be found in Lynch syndrome (LS)-associated colorectal carcinoma and in 15% of sporadic colorectal cancer (CRC). Outcome of MMR-deficiency testing is important for surgical decisions as extended colectomy is recommended in young LS-patients with CRC. Moreover, the finding of a dMMR tumour has consequences for the choices of adjuvant chemotherapy as MMR-deficient CRC is resistant to 5-fluorouracil (5-FU) monotherapy. Aims of our study are to evaluate whether MMR-deficiency testing leads to (1) identification of LS, (2) change in surgical treatment and (3) adjustment of systemic therapy in patients with dMMR CRC.

METHODS

We performed a multicentre, retrospective study, in a community hospital and a University Medical Centre. We included all CRC-patients between 2012 and 2016 who were tested for microsatellite instability. We collected clinical data such as gender, age, referral to clinical geneticist, surgical procedure and choice of chemotherapy.

RESULTS

We analysed 225 CRCs. Twenty-four (10.7%) of 225 CRC were MMR-deficient. Of the 24 patients with dMMR CRC, 18 (75%) were referred to the clinical geneticist and in nine (37%) patients a MMR mutation was identified. In one (4%) of the 24 patients, a subtotal colectomy was performed. In seven (35%) out of 20 MMR deficient patients, the chemotherapy regimen was adjusted.

CONCLUSIONS

The finding of a dMMR CRC had consequences for decisions on chemotherapy in a relative high proportion of patients. We recommend testing in all patients with CRC independent of age at diagnosis, as proper treatment decisions and genetic counselling are very important.

MLH1-rheMac hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques

The discovery of MLH1-rheMac hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques (MLH1-rheMac HNPCC), which is an orthologue of Lynch syndrome in humans, is highly significant in the field of oncology. The hereditary nature of this disease should allow for planned cross-breeding of rhesus macaques to assess the effects of homozygous versus heterozygous MLH1 gene mutations, as well as other comutations and environmental factors that may affect the development of colon cancers. Also, the MLH1-rheMac HNPCC syndrome in rhesus macaques can serve as an important model for development of novel approaches to diagnosis and therapy of Lynch syndrome in human patients.

Over the past two decades, 33 cases of colonic adenocarcinomas have been diagnosed in rhesus macaques (Macaca mulatta) at the nonhuman primate colony of the Keeling Center for Comparative Medicine and Research at The University of Texas MD Anderson Cancer Center. The distinctive feature in these cases, based on PET/computed tomography (CT) imaging, was the presence of two or three tumor lesions in different locations, including proximal to the ileocecal juncture, proximal to the hepatic flexure, and/or in the sigmoid colon. These colon carcinoma lesions selectively accumulated [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) and [¹⁸F]fluoroacetate ([¹⁸F]FACE) at high levels, reflecting elevated carbohydrate and fatty acid metabolism in these tumors. In contrast, the accumulation of [¹⁸F]fluorothymidine ([¹⁸F]FLT) was less significant, reflecting slow proliferative activity in these tumors. The diagnoses of colon carcinomas were confirmed by endoscopy. The expression of MLH1, MSH2, and MSH6 proteins and the degree of microsatellite instability (MSI) was assessed in colon carcinomas. The loss of MLH1 protein expression was observed in all tumors and was associated with a deletion mutation in the MLH1 promoter region and/or multiple single-nucleotide polymorphism (SNP) mutations in the MLH1 gene. All tumors exhibited various degrees of MSI. The pedigree analysis of this rhesus macaque population revealed several clusters of affected animals related to each other over several generations, suggesting an autosomal dominant transmission of susceptibility for colon cancer. The newly discovered hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques, termed MLH1-rheMac, may serve as a model for development of novel approaches to diagnosis and therapy of Lynch syndrome in humans.

Is There a Role for Programmed Death Ligand-1 Testing and Immunotherapy in Colorectal Cancer With Microsatellite Instability? Part I-Colorectal Cancer: Microsatellite Instability, Testing, and Clinical Implications

CONTEXT

- Colorectal cancer (CRC) represents the third most-common cancer in developed countries and is a leading cause of cancer deaths worldwide. Two recognized pathways contribute to CRC development: a more-common chromosomal instability pathway and, in 15% of cases, a deficient mismatch repair or microsatellite instability-high (MSI-H) pathway. The MSI-H CRC can be associated with somatic or germline mutations. Microsatellite status has been recognized as a prognostic and predictive biomarker.

OBJECTIVES

- To summarize the molecular pathways of CRC, with an emphasis on the MSI (mismatch repair) pathway; the recommended MSI testing algorithms and interpretation; and the prognostic and predictive role of MSI-H status in personalized treatment, including adjuvant chemotherapy, targeted therapy, and immune checkpoint inhibitor therapy.

DATA SOURCES

- A PubMed (US National Library of Medicine, Bethesda, Maryland) review was performed for articles pertaining to CRC, MSI and mismatch repair systems, molecular classification, immune response, programmed death receptor-1/programmed death ligand-1, and immunotherapy.

CONCLUSIONS

- Although the TNM classification of malignant tumor stage remains the key determinant of CRC prognosis and treatment, there are considerable stage-independent, interindividual differences in clinical outcome and therapy response by patients. In addition, MSI-H status has an important role in CRC management and can be reliably detected by molecular and immunohistochemistry techniques and genetic testing. Efforts must be made to identify whether MSI-H CRC is germline or sporadic to ensure appropriate treatment, accurate prognosis, and risk assessment for relatives. Microsatellite status has been recognized as a good prognostic indicator and is predictive of a poor response to 5-fluorouracil-based chemotherapy and a good response to programmed death ligand-1 inhibitor pembrolizumab in metastatic/refractory MSI-H CRC.

Feasibility of Segmental Colectomy Followed by Endoscopic Surveillance as a Treatment Strategy for Colorectal Cancer Patients with Lynch Syndrome

BACKGROUND

Initial surgical procedures for colorectal cancer (CRC) patients with Lynch syndrome remain controversial. This study assessed the validity of segmental colectomy (SGC) followed by endoscopic surveillance as a treatment strategy for CRC patients with Lynch syndrome.

METHODS

Among consecutive patients who underwent surgery for primary CRC between April 1985 and December 2014, 49 patients were observed to have germline mutations in a mismatch repair gene, and 38 patients who underwent SGC followed by periodic endoscopic surveillance at our institution were evaluated for metachronous CRC, need for secondary surgery, and the details of endoscopic surveillance.

RESULTS

Of the 38 patients who underwent SGC followed by periodic endoscopic surveillance at our institution, 6 (15.8%) patients showed metachronous CRC, 3 (7.9%) patients underwent endoscopic resection, and the other 3 patients (7.9%) underwent secondary surgery. The dispersion of the endoscopic surveillance interval was significantly greater in patients with metachronous CRC (364 ± 332.9 days) than in those without metachronous CRC (370 ± 129.7 days; p < 0.001).

CONCLUSIONS

SGC followed by annual endoscopic surveillance was feasible as a treatment strategy for CRC patients with Lynch syndrome, because the incidence of metachronous CRC and the need for secondary surgery were low. Annual and periodic endoscopic surveillance might be essential for early detection of metachronous CRC and prevention of secondary surgery because of metachronous CRC in CRC patients with Lynch syndrome after SGC.

Mismatch repair deficiency commonly precedes adenoma formation in Lynch Syndrome-Associated colorectal tumorigenesis

Lynch syndrome is a cancer predisposition syndrome caused by germline mutations in mismatch repair (MMR) genes. MMR deficiency is a ubiquitous feature of Lynch syndrome-associated colorectal adenocarcinomas; however, it remains unclear when the MMR-deficient phenotype is acquired during tumorigenesis. To probe this issue, the present study examined genetic alterations and MMR statuses in Lynch syndrome-associated colorectal adenomas and adenocarcinomas, in comparison with sporadic adenomas. Among the Lynch syndrome-associated colorectal tumors, 68 of 86 adenomas (79%) and all adenocarcinomas were MMR-deficient, whereas all the sporadic adenomas were MMR-proficient, as determined by microsatellite instability testing and immunohistochemistry for MMR proteins. Sequencing analyses identified APC or CTNNB1 mutations in the majority of sporadic adenomas (58/84, 69%) and MMR-proficient Lynch syndrome-associated adenomas (13/18, 72%). However, MMR-deficient Lynch syndrome-associated adenomas had less APC or CTNNB1 mutations (25/68, 37%) and frequent frameshift RNF43 mutations involving mononucleotide repeats (45/68, 66%). Furthermore, frameshift mutations affecting repeat sequences constituted 14 of 26 APC mutations (54%) in MMR-deficient adenomas whereas these frameshift mutations were rare in MMR-proficient adenomas in patients with Lynch syndrome (1/12, 8%) and in sporadic adenomas (3/52, 6%). Lynch syndrome-associated adenocarcinomas exhibited mutation profiles similar to those of MMR-deficient adenomas. Considering that WNT pathway activation sufficiently drives colorectal adenoma formation, the distinct mutation profiles of WNT pathway genes in Lynch syndrome-associated adenomas suggest that MMR deficiency commonly precedes adenoma formation.

The association of low penetrance genetic risk modifiers with colorectal cancer in lynch syndrome patients: a systematic review and meta-analysis

Lynch syndrome (LS) is a highly penetrant inherited cancer predisposition syndrome accounting for approximately 1000 cases of colorectal cancer (CRC) in the UK annually. LS is characterised by autosomal dominant inheritance and germline mutations in DNA mismatch repair genes. The penetrance is highly variable and the reasons for this have not been fully elucidated. This study investigates whether low penetrance genetic risk factors may result in phenotype modification in LS patients. To conduct a systematic literature review and meta-analysis to assess the association between low penetrance genetic risk modifiers and CRC in LS patients. A systematic review was conducted of the PubMed and HuGENet databases. Eligibility of studies was determined by pre-defined criteria. Included studies were analysed via the per-allele model and assessed by pooled odds ratios and establishing 95% confidence intervals. Study heterogeneity was assessed via Cochrane's Q statistic and I2 values. Publication bias was evaluated with funnel plots. Subgroup analysis was conducted on gender. Statistical software used was the Metafor package for the R programme version 3.1.3. Sixty-four polymorphisms were identified and sufficient data was available for analysis of ten polymorphisms, with between 279 and 1768 CRC cases per polymorphism. None demonstrated association with CRC risk in LS patients. However in sub-group analysis the polymorphism rs16892766 (8q23.3) was significant in males (OR 1.53, 95% CI 1.12-2.10). The variable phenotype presentation of the disease still remains largely unexplained, and further investigation is warranted. Other factors may also be influencing the high variability of the disease, such as environmental factors, copy number variants and epigenetic alterations. Investigation into these areas is needed as well as larger and more definitive studies of the polymorphisms analysed in this study.

A comparison between Lynch syndrome and sporadic colorectal cancer survivors' satisfaction with their healthcare providers

This study evaluated provider satisfaction in a sample of colorectal cancer (CRC) survivors with and without Lynch syndrome (LS). Participants were case–case‐matched CRC survivors with (n = 75) or without (n = 75) LS (mean age of 55; range: 27–93). Participants completed a mailed questionnaire assessing demographics, clinical characteristics, healthcare utilization, psychosocial variables, and provider satisfaction. LS CRC survivors reported lower provider satisfaction scores on three subscales of the Primary Care Assessment Survey: communication (78.14 vs. 83.96; P < 0.05), interpersonal treatment (78.58 vs. 85.30; P < 0.05), and knowledge of the patient (60.34 vs. 69.86; P < 0.01). Among LS CRC survivors, predictors for mean communication and trust subscale scores were location of treatment and socioeconomic status. Higher mean depression scores also were associated with trust, while social support predicted higher satisfaction with communication. Sporadic CRC survivor satisfaction is driven largely by age (communication, interpersonal treatment) and patient anxiety (communication), while seeing a provider more often was associated with increased satisfaction with knowledge of the patient. LS CRC survivors reported lower levels of provider satisfaction than sporadic CRC survivors. LS survivors who received care at The University of Texas MD Anderson Cancer Center, a comprehensive cancer center (CCC), reported higher satisfaction than those receiving care at other institutions. Depressive symptoms and socioeconomic status may impact provider satisfaction ratings. Exploration of other potential predictors of provider satisfaction should be examined in this population. Additionally, further research is needed to examine the potential impact of provider satisfaction on adherence to medical recommendations in LS CRC survivors, particularly those being treated outside of CCCs.

Hereditary cancer syndromes as model systems for chemopreventive agent development

Research in chemoprevention has undergone a shift in emphasis for pragmatic reasons from large, phase III randomized studies to earlier phase studies focused on safety, mechanisms, and utilization of surrogate endpoints such as biomarkers instead of cancer incidence. This transition permits trials to be conducted in smaller populations and at substantially reduced costs while still yielding valuable information. This article will summarize some of the current chemoprevention challenges and the justification for the use of animal models to facilitate identification and testing of chemopreventive agents as illustrated though four inherited cancer syndromes. Preclinical models of inherited cancer syndromes serve as prototypical systems in which chemopreventive agents can be developed for ultimate application to both the sporadic and inherited cancer settings.

Mismatch repair deficient-crypts in non-neoplastic colonic mucosa in Lynch syndrome: insights from an illustrative case

Mono-allelic germline mutations in DNA mismatch repair (MMR) genes lead to Lynch syndrome (LS). Questions remain as to the timing of the inactivation of the wild-type allele in LS-associated tumorigenesis. Speculation exists that it happens after the neoplasia has been initiated. However, a recent study reported the presence of MMR-deficiency in non-neoplastic colonic crypts in LS; thus the possibility can be raised that these crypts may be tumor precursors, and as such, biallelic loss of MMR may occur prior to neoplasia. Here we report a unique case that showed findings supporting both of the two seemingly conflicting notions. The patient was a 40-year-old female with LS, MSH2 type, who underwent a segmental colectomy for an adenocarcinoma. By immunohistochemistry, the carcinoma lost MSH2/MSH6. Interestingly, there was also complete loss of MSH2/MSH6 in a distinct focus of 20 colonic crypts that were morphologically non-neoplastic, thus supporting the possibility of biallelic loss of MMR before initiation of neoplasia. However, in a separate adenoma, MMR was preserved in neoplastic glands with low grade dysplasia and lost only in glands with high grade dysplasia, i.e., MMR loss after tumor initiation. These are relevant findings with regard to the timing of MMR deficiency in LS tumorigenesis, and bring forth the possibility that varied tumorigenic pathways may exist. Additionally, we observed that the MMR-deficient non-neoplastic crypts harbored increased intraepithelial CD8-positive T-lymphocytes similar to the patient's carcinoma, providing a potential new venue for the study of the natural antitumor immune responses in LS individuals.

Race and colorectal cancer screening compliance among persons with a family history of cancer

AIM: To determine compliance to colorectal cancer (CRC) screening guidelines among persons with a family history of any type of cancer and investigate racial differences in screening compliance.

METHODS: We used the 2007 Health Information National Trends Survey and identified 1094 (27.4%) respondents (weighted population size = 21959672) without a family history of cancer and 3138 (72.6%) respondents (weighted population size = 58201479) with a family history of cancer who were 50 years and older. We defined compliance with CRC screening as the use of fecal occult blood testing within 1 year, sigmoidoscopy within 5 years, or colonoscopy within 10 years. We compared compliance with CRC screening among those with and without a family member with a history of cancer.

RESULTS: Overall, those with a family member with cancer were more likely to be compliant with CRC screening (64.9% vs 55.1%; OR = 1.45; 95%CI: 1.20-1.74). The absolute increase in screening rates associated with family history of cancer was 8.2% among whites. Hispanics had lowest screening rates among those without family history of cancer 41.9% but had highest absolute increase (14.7%) in CRC screening rate when they have a family member with cancer. Blacks had the lowest absolute increase in CRC screening (5.3%) when a family member has a known history of cancer. However, the noted increase in screening rates among blacks and Hispanics when they have a family member with cancer were not higher than whites without a family history of cancer: (54.5% vs 58.7%; OR = 1.16; 95%CI: 0.72-1.88) for blacks and (56.7% vs 58.7%; OR = 1.25; 95%CI: 0.72-2.18) for Hispanics.

CONCLUSION: While adults with a family history of any cancer were more likely to be compliant with CRC screening guidelines irrespective of race/ethnicity, blacks and Hispanics with a family history of cancer were less likely to be compliant than whites without a family history. Increased burden from CRC among blacks may be related to poor uptake of screening among high-risk groups.

Lynch syndrome-associated neoplasms: a discussion on histopathology and immunohistochemistry

It was a century ago that Warthin, a pathologist, first described the clinical condition now known as Lynch syndrome. One hundred years later, our understanding of this syndrome has advanced significantly. Much of the progress took place over the last 25 years and was marked by a series of interacting developments from the disciplines of clinical oncology, pathology, and molecular genetics, with each development serving to guide or enhance the next. The advancement of our understanding about the pathology of Lynch syndrome associated tumors exemplifies such intimate interplay among disciplines. Today, accumulative knowledge has enabled surgical pathologists to detect tumors that are likely to be associated with Lynch syndrome, and the pathologist is playing an increasingly more important role in the care of these patients. The pathologist's ability is afforded primarily by information gained from tumor histopathology and by DNA mismatch repair protein immunohistochemistry. It is therefore pertinent both for the pathologists to accurately ascertain this morphologic information, and for all that are involved in the care of these patients to thoroughly understand the implications of such information. This article provides an overview of the development of histopathology and immunohistochemistry in Lynch syndrome-associated tumors, particularly in colorectal and endometrial cancers, and outlines the issues and current status of these specific pathologic aspects in not only the major tumors but also those less commonly seen or only newly reported in Lynch syndrome patients.

ACMG technical standards and guidelines for genetic testing for inherited colorectal cancer (Lynch syndrome, familial adenomatous polyposis, and MYH-associated polyposis)

Lynch syndrome, familial adenomatous polyposis, and Mut Y homolog (MYH)-associated polyposis are three major known types of inherited colorectal cancer, which accounts for up to 5% of all colon cancer cases. Lynch syndrome is most frequently caused by mutations in the mismatch repair genes MLH1, MSH2, MSH6, and PMS2 and is inherited in an autosomal dominant manner. Familial adenomatous polyposis is manifested as colonic polyposis caused by mutations in the APC gene and is also inherited in an autosomal dominant manner. Finally, MYH-associated polyposis is caused by mutations in the MUTYH gene and is inherited in an autosomal recessive manner but may or may not be associated with polyps. There are variants of both familial adenomatous polyposis (Gardner syndrome--with extracolonic features--and Turcot syndrome, which features medulloblastoma) and Lynch syndrome (Muir-Torre syndrome features sebaceous skin carcinomas, and Turcot syndrome features glioblastomas). Although a clinical diagnosis of familial adenomatous polyposis can be made using colonoscopy, genetic testing is needed to inform at-risk relatives. Because of the overlapping phenotypes between attenuated familial adenomatous polyposis, MYH-associated polyposis, and Lynch syndrome, genetic testing is needed to distinguish among these conditions. This distinction is important, especially for women with Lynch syndrome, who are at increased risk for gynecological cancers. Clinical testing for these genes has progressed rapidly in the past few years with advances in technologies and the lower cost of reagents, especially for sequencing. To assist clinical laboratories in developing and validating testing for this group of inherited colorectal cancers, the American College of Medical Genetics and Genomics has developed the following technical standards and guidelines. An algorithm for testing is also proposed.

Molecular and clinical characteristics of MSH6 germline variants detected in colorectal cancer patients

The MSH6 gene is one of the mismatch repair genes involved in Lynch syndrome and its mutations account for 10-20% of Lynch syndrome. Although previous studies suggested that the difference of the geographical region affects the clinical phenotype of Lynch syndrome, there has been no report on the detailed features of Japanese Lynch syndrome patients carrying an MSH6 mutation. The aim of the present study was to investigate the clinical and molecular features of MSH6 mutation carriers in Japan. Surgically resected 1720 colorectal carcinoma specimens were screened by microsatellite instability (MSI) testing and the MSI-high cases were subjected to a germline mutation analysis of the mismatch repair genes MLH1, MSH2 and MSH6. We investigated the clinical and molecular features of the MSH6 variants, such as the family cancer history, pathological findings, immunohistochemistry, methylation status of the MLH1 promoter and BRAF mutation in the colorectal tumor. Furthermore, the impact of the missense variants on MSH6 protein was predicted by using in silico tools. We identified nine novel pathogenic mutations and eight unclassified missense variants. Among the eight missense variants, three were suspected pathogenic by in silico analysis. We also found that most colorectal cancers in the MSH6 mutation carrier were diagnosed after the age of 50 and were localized distally. Furthermore, the mean age at diagnosis of endometrial cancer in Japanese MSH6 mutation carriers (49.2 years) was earlier than previous reports from Western countries (56.5 years). These results may improve the surveillance program for Japanese MSH6 mutation carriers.

Gynecologic cancer screening and communication with health care providers in women with Lynch syndrome

We evaluated knowledge of gynecologic cancer screening recommendations, screening behaviors, and communication with providers among women with Lynch syndrome (LS). Women aged ≥25 years who were at risk for LS-associated cancers completed a semi-structured interview and a questionnaire. Of 74 participants (mean age 40 years), 61% knew the appropriate age to begin screening, 75-80% correctly identified the recommended screening frequency, and 84% reported no previous screening endometrial biopsy. Women initiated discussions with their providers about their LS cancer risks, but many used nonspecific terms or relied on family history. Most were not offered high-risk screening options. While many women were aware of risk-appropriate LS screening guidelines, adherence was suboptimal. Improving communication between women and their providers regarding LS-related gynecologic cancer risk and screening options may help improve adherence.

Mismatch repair proteins in recurrent prostate cancer

Normal cell function requires strict control over the repair of DNA damage, which prevents excessive mutagenesis. An enhanced accumulation of mutations results in the multistep process generally known as carcinogenesis. Defects in repair pathways fuel such mutagenesis by allowing reiterative cycles of mutation, selection, and clonal expansion that drive cancer progression. The repair of mismatches is an important mechanism in the prevention of such genetic instability. In addition, proteins of this pathway have the unique ability to function in DNA damage response by inducing apoptosis when irreparable damage is encountered. Though originally identified primarily in association with a predisposition to hereditary colon cancer, mismatch repair defects have been identified in many other cancer types, including prostate cancer. From the first discovery of microsatellite instability in prostate cancer cell lines and tumor samples, variations in protein levels and a possible association with recurrence and aggression of disease have been described. Current results suggest that the involvement of mismatch repair proteins in prostate cancer may differ from that found in colorectal cancer, in the type of proteins and protein defects involved and the type of causative mutations. Additional work is clearly needed to investigate this involvement and the possibility that such defects may affect treatment response and androgen independence.

Lynch syndrome-associated breast cancers do not overexpress chromosome 11-encoded mucins

Mismatch repair-deficient breast cancers may be identified in Lynch syndrome mutation carriers, and have clinicopathological features in common with mismatch repair-deficient colorectal and endometrial cancers such as tumour-infiltrating lymphocytes and poor differentiation. Mismatch repair-deficient colorectal cancers frequently show mucinous differentiation associated with upregulation of chromosome 11 mucins. The aim of this study was to compare the protein expression of these mucins in mismatch repair-deficient and -proficient breast cancers. Cases of breast cancer (n=100) were identified from families where (1) both breast and colon cancer co-occurred and (2) families met either modified Amsterdam criteria or had at least one early-onset (<50 years) colorectal cancer. Tumour sections were stained for the epithelial mucins, MUC2, MUC5AC, MUC5B and MUC6, and the homeobox protein CDX2, a regulator of MUC2 expression. In all, 16 mismatch repair-deficient Lynch syndrome breast cancers and 84 non-Lynch breast cancers were assessed for altered mucin expression. No significant difference in the expression of MUC2, MUC5AC or MUC6 was observed between the mismatch repair-deficient and mismatch repair-proficient breast cancers; however, there was a trend for mismatch repair-deficient tumours to express high levels of MUC5B less frequently (P=0.07, OR=0.2 (0.0-1.0)). Co-expression of two or more gel-forming mucins was common. Ectopic expression of CDX2 was associated with expression of MUC2 (P=0.035, OR=8.7 (1.3-58.4)). Mismatch repair-deficient breast cancers do not show differential expression of the mucins genes on chromosome 11 when compared with mismatch repair-proficient breast cancers, in contrast with mismatch repair-deficient colorectal and endometrial cancers, which frequently have increased mucin protein expression when compared with their mismatch repair-proficient counterparts. In addition, ectopic CDX2 expression is positively associated with de novo MUC2 expression.

Refining the role of PMS2 in Lynch syndrome: germline mutational analysis improved by comprehensive assessment of variants

BACKGROUND AND AIM

The majority of mismatch repair (MMR) gene mutations causing Lynch syndrome (LS) occur either in MLH1 or MSH2. However, the relative contribution of PMS2 is less well defined. The aim of this study was to evaluate the role of PMS2 in LS by assessing the pathogenicity of variants of unknown significance (VUS) detected in the mutational analysis of PMS2 in a series of Spanish patients.

METHODS

From a cohort of 202 LS suspected patients, 13 patients showing loss of PMS2 expression in tumours were screened for germline mutations in PMS2, using a long range PCR based strategy and multiplex ligation dependent probe amplification (MLPA). Pathogenicity assessment of PMS2 VUS was performed evaluating clinicopathological data, frequency in control population and in silico and in vitro analyses at the RNA and protein level.

RESULTS

Overall 25 different PMS2 DNA variants were detected. Fourteen were classified as polymorphisms. Nine variants were classified as pathogenic: seven alterations based on their molecular nature and two after demonstrating a functional defect (c.538-3C>G affected mRNA processing and c.137G>T impaired MMR activity). The c.1569C>G variant was classified as likely neutral while the c.384G>A remained as a VUS. We have also shown that the polymorphic variant c.59G>A is MMR proficient.

CONCLUSIONS

Pathogenic PMS2 mutations were detected in 69% of patients harbouring LS associated tumours with loss of PMS2 expression. In all, PMS2 mutations account for 6% of the LS cases identified. The comprehensive functional analysis shown here has been useful in the classification of PMS2 VUS and contributes to refining the role of PMS2 in LS.

Precancerous lesions in colorectal cancer

Colorectal cancer (CRC) is the third most common cause of cancer death in the world. The incidence rate (ASR) and age distribution of this disease differ between most of African-Middle-Eastern (AMAGE) and North America and Europe for many reasons. However, in all areas, "CRC" is considered as one of the most preventable cancers, because it might develop from variant processes like polyps and IBD in addition to the genetic pathogenesis which became very well known in this disease. We tried in this paper to review all the possible reasons of the differences in incidence and age between the west and AMAGE. Also we reviewed all the mutations that lead to the hereditary and familiar clustering of this disease with the correlations with the surrounding food and environment of different areas. Then, we focused on the precancerous pathology of this disease with special focusing on early detection depending on new endoscopy technology and most important genetic studies. We lastly reviewed the evidence of some of the surveillance and put suggestions about future surveillance programs and how important those programs are on the psychological aspect of the patients and their families.

Bethesda criteria for microsatellite instability testing: impact on the detection of new cases of Lynch syndrome

In 1997 Bethesda Guidelines (BG) were established and in 2004 those criteria were revised (RBG), with the main goal of selecting colorectal cancers (CRC) that should be subjected to microsatellite instability (MSI) testing. High microsatellite instability (MSI-H) is an intermediate marker for mutational analysis of the mismatch repair (MMR) genes involved in the genesis of Lynch Syndrome (LS). We aimed to evaluate and compare BG/RBG in the detection of MSI-H and subsequent identification of pathogenic MMR genes mutations. We included 174 patients with CRC and indication for MSI analysis according to BG or RBG. MSI testing was performed with the Bethesda markers and mutational analysis of MLH1, MSH2 and MSH6 genes undertaken with DGGE, MLPA and direct sequencing. One hundred fourteen of 174 patients (65.5 %) fulfilled BG and all of them RBG. With the BG, MSI-H was detected in 37/114 (32.5 %) CRCs and mutational analysis was positive in 14/37 (37.8 %) patients. The RBG led to detection of MSI-H in 49/174 (28.2 %) of the CRCs, having the mutational analysis been positive in 16/49 (32.7 %) patients. We could identify 14/114 (12.3 %) new cases of LS, through BG and 16/174 (9.2 %) via RBG. BG presented a similar overall percentage for the detection of MSI-H and mutations when compared with RBG. RBG implicated the analysis of more patients, though they gave rise to detection of two additional LS cases. This difference has a significant impact on the establishment of preventive measures, mainly for CRC, in all the mutation-carriers belonging to these families.

Risks of less common cancers in proven mutation carriers with lynch syndrome

PURPOSE

Patients with Lynch syndrome are at high risk for colon and endometrial cancer, but also at an elevated risk for other less common cancers. The purpose of this retrospective cohort study was to provide risk estimates for these less common cancers in proven carriers of pathogenic mutations in the mismatch repair (MMR) genes MLH1, MSH2, and MSH6.

PATIENTS AND METHODS

Data were pooled from the German and Dutch national Lynch syndrome registries. Seven different cancer types were analyzed: stomach, small bowel, urinary bladder, other urothelial, breast, ovarian, and prostate cancer. Age-, sex- and MMR gene-specific cumulative risks (CRs) were calculated using the Kaplan-Meier method. Sex-specific incidence rates were compared with general population incidence rates by calculating standardized incidence ratios (SIRs). Multivariate Cox regression analysis was used to estimate the impact of sex and mutated gene on cancer risk.

RESULTS

The cohort comprised 2,118 MMR gene mutation carriers (MLH1, n = 806; MSH2, n = 1,004; MSH6, n = 308). All cancers were significantly more frequent than in the general population. The highest risks were found for male small bowel cancer (SIR, 251; 95% CI, 177 to 346; CR at 70 years, 12.0; 95% CI, 5.7 to 18.2). Breast cancer showed an SIR of 1.9 (95% CI, 1.4 to 2.4) and a CR of 14.4 (95% CI, 9.5 to 19.3). MSH2 mutation carriers had a considerably higher risk of developing urothelial cancer than MLH1 or MSH6 carriers.

CONCLUSION

The sex- and gene-specific differences of less common cancer risks should be taken into account in cancer surveillance and prevention programs for patients with Lynch syndrome.

Molecular pathways in colorectal cancer

Colorectal cancer (CRC) is the second most common newly diagnosed cancer and accounts for the second highest number of cancer related deaths in Australia, the third worldwide and of increasing importance in Asia. It arises through cumulative effects of inherited genetic predispositions and environmental factors. Genomic instability is an integral part in the transformation of normal colonic or rectal mucosa into carcinoma. Three molecular pathways have been identified: these are the chromosomal instability (CIN), the microsatellite instability (MSI), and the CpG Island Methylator Phenotype (CIMP) pathways. These pathways are not mutually exclusive, with some tumors exhibiting features of multiple pathways. Germline mutations are responsible for hereditary CRC syndromes (accounting for less than 5% of all CRC) while a stepwise accumulation of genetic and epigenetic alterations results in sporadic CRC. This review aims to discuss the genetic basis of hereditary CRC and the different pathways involved in the process of colorectal carcinogenesis.

Comprehensive functional assessment of MLH1 variants of unknown significance

Lynch syndrome is associated with germline mutations in DNA mismatch repair (MMR) genes. Up to 30% of DNA changes found are variants of unknown significance (VUS). Our aim was to assess the pathogenicity of eight MLH1 VUS identified in patients suspected of Lynch syndrome. All of them are novel or not previously characterized. For their classification, we followed a strategy that integrates family history, tumor pathology, and control frequency data with a variety of in silico and in vitro analyses at RNA and protein level, such as MMR assay, MLH1 and PMS2 expression, and subcellular localization. Five MLH1 VUS were classified as pathogenic: c.[248G>T(;)306G>C], c.[780C>G;788A>C], and c.791-7T>A affected mRNA processing, whereas c.218T>C (p.L73P) and c.244A>G [corrected] (p.T82A) impaired MMR activity. Two other VUS were considered likely neutral: the silent c.702G>A variant did not affect mRNA processing or stability, and c.974G>A (p.R325Q) did not influence MMR function. In contrast, variant c.25C>T (p.R9W) could not be classified, as it associated with intermediate levels of MMR activity. Comprehensive functional assessment of MLH1 variants was useful in their classification and became relevant in the diagnosis and genetic counseling of carrier families.

Lynch syndrome: barriers to and facilitators of screening and disease management

Background

Lynch syndrome is a hereditary cancer with confirmed carriers at high risk for colorectal (CRC) and extracolonic cancers. The purpose of the current study was to develop a greater understanding of the factors influencing decisions about disease management post-genetic testing.

Methods

The study used a grounded theory approach to data collection and analysis as part of a multiphase project examining the psychosocial and behavioral impact of predictive DNA testing for Lynch syndrome. Individual and small group interviews were conducted with individuals from 10 families with the MSH2 intron 5 splice site mutation or exon 8 deletion. The data from confirmed carriers (n = 23) were subjected to re-analysis to identify key barriers to and/or facilitators of screening and disease management.

Results

Thematic analysis identified personal, health care provider and health care system factors as dominant barriers to and/or facilitators of managing Lynch syndrome. Person-centered factors reflect risk perceptions and decision-making, and enduring screening/disease management. The perceived knowledge and clinical management skills of health care providers also influenced participation in recommended protocols. The health care system barriers/facilitators are defined in terms of continuity of care and coordination of services among providers.

Conclusions

Individuals with Lynch syndrome often encounter multiple barriers to and facilitators of disease management that go beyond the individual to the provider and health care system levels. The current organization and implementation of health care services are inadequate. A coordinated system of local services capable of providing integrated, efficient health care and follow-up, populated by providers with knowledge of hereditary cancer, is necessary to maintain optimal health.

Rapid development of colorectal neoplasia in patients with Lynch syndrome

BACKGROUND & AIMS

Patients with Lynch syndrome have a high risk for colorectal adenomas and carcinomas. We evaluated the development of colorectal neoplasia in these patients.

METHODS

We assessed serial colonoscopy findings from 54 persons from 29 pedigrees with pathogenic mutations in MSH2 or MLH1; we evaluated the development of colorectal neoplasia by age, sex, tumor location, and number (mean follow-up time, 9.3 years; colonoscopy interval, 1.7 ± 1.2 years; 112 adenomas and 31 cancers). Differences in colorectal phenotype were analyzed by genotype, and dwell time was calculated for advanced neoplasias.

RESULTS

Among mutation carriers, the cumulative risk of colorectal neoplasia was 43% by age 40 years and 72% by 80 years. There were no statistically significant associations between time to development of colorectal neoplasia and sex or mutation type. Most female patients had left-sided neoplasms, whereas most male patients developed right-sided lesions. The mean cumulative numbers of neoplastic lesions in patients were 1.3 ± 0.5 by age 30 years and 7.6 ± 6.8 by age 80 years. Polyp dwell time was 33.0 ± 16.2 months and 35.2 ± 22.3 months for advanced adenoma and colorectal cancer, respectively. The 5-year survival rate for patients with colorectal cancer was 96%.

CONCLUSIONS

High percentages of individuals with pathogenic mutations in MSH2 or MLH1 develop colorectal neoplasia by age 40. Left-sided colorectal neoplasias are more frequent in female patients. The development of 3 or more colorectal neoplasms by age 30 years indicates a possible polyposis syndrome rather than Lynch syndrome. Polyp dwell time is short for advanced neoplasias, arguing for annual colonoscopic screening and surveillance.

Ki-67 and Bcl-2 antigen expression in adenomatous colorectal polyps from women with breast cancer

BACKGROUND

The aim of this study was to evaluate Ki-67 and Bcl-2 antigen expression in colorectal polyps from women with breast cancer.

METHODS

A randomized, controlled study was carried out in 35 women, either with or without breast cancer, who had adenomatous colorectal polyps. The patients were divided into two groups: group A (without breast cancer; control group; n = 17) and group B (with breast cancer; study group; n = 18). Immunohistochemistry was performed on the colorectal polyps to evaluate Ki-67 and Bcl-2 antigen expression. Student's t-test and the chi(2) test were used for the statistical analysis of Ki-67 and Bcl-2 expression, respectively. Statistical significance was established as P < 0.05.

RESULTS

The mean percentage of Ki-67-stained nuclei in groups A and B was 36.25 +/- 2.31 and 59.44 +/- 3.34 (+/- SEM), respectively (P < 0.0001), while the percentage of cases with cells expressing Bcl-2 in groups A and B was 23.5 and 77.8%, respectively (P < 0.001).

CONCLUSIONS

In the present study, there was greater proliferative activity and greater expression of the antiapoptotic protein Bcl-2 in the colorectal polyps of women with breast cancer.

Risk and epidemiological time trends of gastric cancer in Lynch syndrome carriers in the Netherlands

BACKGROUND & AIMS

Although gastric cancer forms part of the Lynch syndrome tumor spectrum, the risk of developing gastric cancer in Lynch syndrome families is unknown, resulting in a lack of clear guidelines for surveillance. The aim of this study was to evaluate incidence trends and risk of developing gastric cancer among Lynch syndrome mutation carriers in a Western population.

METHODS

Lynch syndrome mutation carriers were selected from the Dutch Hereditary Cancer Registry. The gastric cancer incidence in Lynch syndrome mutation carriers was compared to the gastric cancer incidence in the Dutch population between 1970 and 2003. Standardized incidence ratios were calculated by a Poisson model. Cumulative risks were calculated by Kaplan-Meier analysis.

RESULTS

Overall, 2014 Lynch syndrome mutation carriers were identified. Gastric cancer was diagnosed in 32 (1.6%) subjects (male/female: 21/11), 22 (69%) of them had a negative family history of gastric cancer. The standardized incidence ratios of gastric cancer was 3.4 (95% confidence interval, 2.1-5.2) and showed a nonsignificant decline between 1970 and 2003 (P = .30). Absolute risk of developing gastric cancer also showed no significant change over time (P = .51). Lifetime risk of developing gastric cancer was 8.0% in males vs 5.3% in females (P = .02), and 4.8% and 9% for MLH1 and MSH2 carriers, respectively. None of the 378 MSH6 carriers developed gastric cancer (P = .002 vs MLH1 and MSH2 combined lifetime risk).

CONCLUSIONS

Lynch syndrome mutation carriers have a substantial risk for gastric cancer, in particular patients with an MLH1 or MSH2 mutation. Family history for gastric cancer is a poor indicator for individual risk. Surveillance gastroscopy for Lynch syndrome patients carrying an MLH1 or MSH2 mutation should therefore be considered.

Penetrance of HNPCC-related cancers in a retrolective cohort of 12 large Newfoundland families carrying a MSH2 founder mutation: an evaluation using modified segregation models

Background

Accurate risk (penetrance) estimates for associated phenotypes in carriers of a major disease gene are important for genetic counselling of at-risk individuals. Population-specific estimates of penetrance are often needed as well. Families ascertained from high-risk disease clinics provide substantial data to estimate penetrance of a disease gene, but these estimates must be adjusted for possible specific sources of bias.

Methods

A cohort of 12 independently ascertained HNPCC families harbouring a founder MSH2 mutation was identified from a cancer genetics clinic in St. John's, Newfoundland, Canada. Carrier status was known for 247 family members but phenotype information on up to 85 additional relatives with unknown carrier status was available; using modified segregation models these additional individuals could be included in the analyses. Three HNPCC-related phenotypes were evaluated as age at diagnosis of: any HNPCC cancer (first cancer), colorectal cancer (CRC), and endometrial cancer (EC) for females.

Results

Lifetime (age 70) risk estimates for male and female carriers were similar for developing any HNPCC cancer (Males = 98.2%, 95% Confidence Interval (CI) = (93.8%, 99.9%); Females = 92.8%, 95% CI = (82.4%, 99.1%)) but female carriers experienced substantially reduced lifetime risk for developing CRC compared to male carriers (Females = 38.9%, 95% CI = (24.2%, 62.1%); Males = 84.5%, 95% CI = (67.3%, 91.3%)). Female non-carriers had very low lifetime risk for these two outcomes while male non-carriers had lifetime risks intermediate to the female carriers and non-carriers. Female carriers had a lifetime risk of developing EC of 82.4%. Relative risks for developing any HNPCC cancer (carriers relative to non-carriers) were substantially greater for females compared to their male counterparts (Females = 54.8, 95%CI = (4.4, 379.8); Males = 9.7, 95% CI = (0.3, 23.8)). Relative risks for developing CRC at age 70 were substantially greater for females compared to their male counterparts (Females = 23.7, 95%CI = (5.6, 137.9); Males = 6.8%, 95% CI = (2.3, 66.2)). However, the risk of developing CRC decreased with age among both genders.

Conclusion

The proposed modified segregation-based models used to estimate age-specific risks for HNPCC phenotypes can reduce bias due to ascertainment and missing genotype information as well as provide estimates of absolute and relative risks.

Estrogens, MSI and Lynch syndrome-associated tumors

Estrogens play a major role in the biology of hormone-responsive tissues but also in the normal physiology of various non-typical hormone-responsive tissues. In disease, estrogens have been associated with tumor development, in particular with tumors such as breast, endometrium, ovary and prostate. In this paper we will review the molecular mechanisms by which estrogens are involved in cancer development, with a special focus in Lynch syndrome related neoplasia. Further, we discuss the role estrogens might have on cell proliferation and apoptosis, how estrogens metabolites can induce DNA damage and we discuss a possible connection between estrogens and changes in DNA (hypo- and hyper) methylation. In this review we will also address the protective effect that high levels of estrogens have in MMR related neoplasias.

Hereditary colorectal cancer syndromes: familial adenomatous polyposis and lynch syndrome

Familial colorectal cancer (CRC) accounts for 10% to 20% of all cases of CRC. Two major autosomal dominant forms of heritable CRC are familial adenomatous polyposis (FAP) and Lynch syndrome (also known as hereditary nonpolyposis colorectal cancer). Along with the risk for CRC, both syndromes are associated with elevated risk for other tumors. Improved understanding of the genetic basis of these diseases has not only facilitated the identification and screening of at-risk individuals and the development of prophylactic or early-stage intervention strategies but also provided better insight into sporadic CRC. This article reviews the clinical and genetic characteristics of FAP and Lynch syndrome, recommended screening and surveillance practices, and appropriate surgical and nonsurgical interventions.

Cancer genetics: a primer for surgeons

Contemporary ideas of carcinogenesis envisage a series of stochastic genetic changes that confer a selective growth advantage over healthy cells. These changes collectively lead to the disruption of coordinated networks of intercellular communication and cause a fundamental change in cellular behavior, which affects processes, such as proliferation, differentiation, and apoptosis. This progressive dysregulation of cellular function implies that cancer is not a morphologic entity, but a process in which the malignant phenotype is gradually acquired.