Refining the Amsterdam Criteria and Bethesda Guidelines: testing algorithms for the prediction of mismatch repair mutation status in the familial cancer clinic

Unveiling pembrolizumab effectiveness in diverse subtypes of MSI-high endometrial cancers

OBJECTIVE

The efficacy of pembrolizumab in patients with microsatellite instability (MSI)-high cancers has been reported; however, the differences in efficacy according to the subtypes of MSI-high endometrial cancers (ECs) remain unclear. MSI-high ECs are classified into at least 3 groups based on their molecular characteristics: MLH1 hypermethylated, Lynch-like syndrome (LLS)-associated, and Lynch syndrome (LS)-associated cancers. This study aimed to investigate whether the efficacy of pembrolizumab differs among these 3 groups, and if so, whether EPM2AIP1 immunohistochemistry (IHC), which correlates with MLH1 promoter methylation, can be used to rule out MLH1 methylation cases.

METHODS

This study included 12 patients with MSI-high EC who received pembrolizumab treatment. Patients were categorized into 3 groups based on MLH1 methylation analysis and the Amsterdam Criteria: MLH1 hypermethylated (sporadic [SP]), LLS-associated, and LS-associated. Patients' medical records were retrospectively reviewed, and the efficacy of treatment was evaluated based on the response rate using the Response Evaluation Criteria in Solid Tumors version 1.1.

RESULTS

The overall response rate was 75% (3/4) in the SP group, while it was 100% including one complete response patient in the LLS-associated and the LS-associated group, respectively. The sensitivity and positive predictive value of EPM2AIP1 IHC for MLH1 methylation were 100% and 66.7%, respectively.

CONCLUSION

Pembrolizumab may be more effective in LLS and LS-associated groups. EPM2AIP1 IHC was less predictive than MLH1 methylation analysis; however, it may be useful for ruling out MLH1 methylation cases due to its high sensitivity. Further studies are needed to determine whether EPM2AIP1 IHC can predict pembrolizumab efficacy.

Two Decades of Progress in Personalized Medicine of Colorectal Cancer in Serbia-Insights from the Institute for Oncology and Radiology of Serbia

BACKGROUND

It is projected that, by 2040, the number of new cases of colorectal cancer (CRC) will increase to 3.2 million, and the number of deaths to 1.6 million, highlighting the need for prevention strategies, early detection and adequate follow-up. In this study, we aimed to provide an overview of the progress in personalized medicine of CRC in Serbia, with results and insights from the Institute for Oncology and Radiology of Serbia (IORS), and to propose guidance for tackling observed challenges in the future.

METHODS

Epidemiological data were derived from official global and national cancer registries and IORS electronic medical records. Germline genetic testing for Lynch syndrome was performed by Next Generation Sequencing. RAS and BRAF mutation analyses were performed using qPCR diagnostic kits.

RESULTS

Epidemiology and risk factors, prevention and early detection programs, as well as treatment options and scientific advances have been described in detail. Out of 103 patients who underwent germline testing for Lynch syndrome, 19 (18.4%) showed a mutation in MMR genes with pathogenic or likely pathogenic significance and 8 (7.8%) in other CRC-associated genes (APC, CHEK2, MUTYH). Of 6369 tested patients, 50.43% had a mutation in KRAS or NRAS genes, while 9.54% had the V600 mutation in the BRAF gene.

CONCLUSIONS

Although significant improvements in CRC management have occurred globally in recent years, a strategic approach leading to population-based systemic solutions is required. The high incidence of young-onset CRC and the growing elderly population due to a rise in life expectancy will be especially important factors for countries with limited healthcare resources like Serbia.

Asymptomatic endometrial cancer with Lynch syndrome; in a woman with primary infertility-A case report and literature review

Lynch syndrome, also called hereditary non-polyposis colorectal cancer, is an autosomal dominant disorder characterized by germline pathogenic mutations in DNA mismatch repair genes-resulting in increased susceptibility to colorectal, endometrial, and other tumors. This case report presents an incidental finding of endometrial cancer with Lynch syndrome during investigation for primary infertility. A 34-year-old woman presented to the fertility clinic with unexplained primary infertility. Investigations showed possible endometrial polyp, 13 × 11 mm in size. Hysteroscopic polypectomy and endometrial biopsy revealed complex endometrial hyperplasia amounting to endometroid adenocarcinoma. The case was discussed at the West of Scotland Gynecology-Oncology MDT meeting-management options including fertility-sparing treatment or radical surgery were presented to the patient and she opted for the latter. A total laparoscopic hysterectomy with bilateral salpingo-oophorectomy was performed with pathology results consistent with well-differentiated endometroid adenocarcinoma Stage 1A. Peritoneal washings showed no malignant cells. Genetic testing confirmed a diagnosis of Lynch syndrome. On further questioning, it was revealed that the patient had a strong family history of colon cancer but had not previously met the criteria for genetic testing. She was referred to colorectal surgeons and underwent colonoscopy. This showed no abnormality; she was therefore scheduled for 2-yearly colonoscopic surveillance.

Fecal Immunochemical Test Screening and Risk of Colorectal Cancer Death

Importance

The fecal immunochemical test (FIT) is widely used for colorectal cancer (CRC) screening, but evidence of its effectiveness is limited.

Objective

To evaluate whether FIT screening is associated with a lower risk of dying from CRC overall, according to cancer location, and within demographic groups.

Design, Setting, and Participants

This nested case-control study in a cohort of screening-eligible people was conducted in 2 large, integrated health systems of racially, ethnically, and socioeconomically diverse members with long-term programs of mailed FIT screening outreach. Eligible participants included people aged 52 to 85 years who died from colorectal adenocarcinoma between 2011 and 2017 (cases); cases were matched in a 1:8 ratio based on age, sex, health-plan membership duration, and geographic area to randomly selected persons who were alive and CRC-free on case's diagnosis date (controls). Data analysis was conducted from January 2002 to December 2017.

Exposures

Completing 1 or more FIT screenings in the 5-year period prior to the CRC diagnosis date among cases or the corresponding date among controls; in secondary analyses, 2- to 10-year intervals were evaluated.

Main Outcomes and Measures

The primary study outcome was CRC death overall and by tumor location. Secondary analyses were performed to assess CRC death by race and ethnicity.

Results

From a cohort of 2 127 128 people, a total of 10 711 participants (3529 aged 60-69 years [32.9%]; 5587 male [52.1%] and 5124 female [47.8%]; 1254 non-Hispanic Asian [11.7%]; 973 non-Hispanic Black [9.1%]; 1929 Hispanic or Latino [18.0%]; 6345 non-Hispanic White [59.2%]) was identified, including 1103 cases and 9608 controls. Among controls during the 10-year period prior to the reference date, 6101 (63.5%) completed 1 or more FITs with a cumulative 12.6% positivity rate (768 controls), of whom 610 (79.4%) had a colonoscopy within 1 year. During the 5-year period, 494 cases (44.8%) and 5345 controls (55.6%) completed 1 or more FITs. In regression analysis, completing 1 or more FIT screening was associated with a 33% lower risk of death from CRC (adjusted odds ratio [aOR], 0.67; 95% CI, 0.59-0.76) and 42% lower risk in the left colon and rectum (aOR, 0.58; 95% CI, 0.48-0.71). There was no association with right colon cancers (aOR, 0.83; 95% CI, 0.69-1.01) but the difference in the estimates between the right colon and left colon or rectum was statistically significant (P = .01). FIT screening was associated with lower CRC mortality risk among non-Hispanic Asian (aOR, 0.37; 95% CI, 0.23-0.59), non-Hispanic Black (aOR, 0.58; 95% CI, 0.39-0.85) and non-Hispanic White individuals (aOR, 0.70; 95% CI, 0.57-0.86) (P for homogeneity = .04 for homogeneity).

Conclusions and Relevance

In this nested case-control study, completing FIT was associated with a lower risk of overall death from CRC, particularly in the left colon, and the associations were observed across racial and ethnic groups. These findings support the use of FIT in population-based screening strategies.

Streamlining the diagnostic pathway for Lynch syndrome in colorectal cancer patients: a 10-year experience in a single Italian Cancer Center

BACKGROUND

Universal screening of colorectal cancer (CRC) patients for Lynch syndrome (LS) through MisMatch Repair (MMR) testing is recommended. BRAF V600E mutation and/or MLH1 promoter methylation (Reflex Testing, RefT)generally rule out LS in MLH1-deficient (dMLH1) patients. We estimated the impact of RefTon genetic counseling (GC) and on the diagnostic yield of genetic testing (GT).

METHODS

Overall, 3199 CRC patients were referred to our center between 2011 and 2021. Patients referred until January 2019 (n=2536) underwent universal MMR testing and were termed 'Cohort A'; among patients after February 2019 (n=663), 'Cohort B', RefT was also performed in dMLH1 patients.

RESULTS

Overall, 401/3199 patients (12.5%) were MMR-deficient (dMMR); 312 (77.8%) in cohort A and 89 (22.2%) inB; 346/401 were dMLH1 (86.3%), 262/312 (83.9%) in cohort A and 84/89 (94.3%) in B. In Cohort A, 91/312 (29.1%) dMMR patients were referred to GC, 69/91 (75.8%) were in the dMLH1 group; 57/69 (82.6%) dMLH1 patients underwent GT and 1/57 (1.7%) had LS. In Cohort B, 3/84 dMLH1 patients did not undergo BRAF testing. Three BRAF wt and not hypermethylated of the remaining 81 dMLH1 patients were referred to GC and GT, and one had LS. This diagnostic pathway reduced GC referrals by 96% (78/81) in Cohort B and increased the diagnostic yield of GT by about 20 times.

CONCLUSION

Our findings support RefT in dMLH1 CRC patients within the LS diagnostic pathway, as it reduces the number of GC sessions needed and increases the diagnostic yield of GT.

Upper Gastrointestinal Cancers and the Role of Genetic Testing

Beyond the few established hereditary cancer syndromes with an upper gastrointestinal cancer component, there is increasing recognition of the contribution of novel pathogenic germline variants (gPVs) to upper gastrointestinal carcinogenesis. The detection of gPVs has potential implications for novel treatment approaches of the index cancer patient as well as long-term implications for surveillance and risk-reducing measures for cancer survivors and far-reaching implications for the patients' family. With widespread availability of multigene panel testing, new associations may be identified with germline-somatic integration being critical to determining true causality of novel gPVs. Comprehensive cancer care should incorporate both somatic and germline testing.

Screening and surveillance for hereditary colorectal cancer

Hereditary colorectal cancer is a type of cancer that is caused by a genetic mutation. Individuals with a family history of colorectal cancer, or who have a known hereditary syndrome, are at an increased risk of developing the disease. Screening and surveillance are important tools for managing the risk of hereditary colorectal cancer. Screening involves a combination of tests that can detect precancerous or cancerous changes in the colon and rectum. Surveillance involves regular follow-up examinations to monitor disease progression and to identify new developments. The frequency and type of screening and surveillance tests may vary depending on an individual's risk factors, genetic profile, and medical history. However, early detection and treatment of hereditary colorectal cancer can significantly improve patient outcomes and reduce mortality rates. By implementing comprehensive screening and surveillance strategies, healthcare providers can help individuals at risk of hereditary colorectal cancer to receive timely interventions and make informed decisions about their health. Specific examples of screening and surveillance tests for hereditary colorectal cancer include colonoscopy, genetic testing, and imaging tests. In this review article, we will discuss detailed screening and surveillance of hereditary colorectal cancer.

Early-Onset GI Cancers: Rising Trends, Genetic Risks, Novel Strategies, and Special Considerations

Cancers in young adults (commonly described as early-onset [EO] cancer) represent a group of malignancies that have unique and challenging biology and genetic, treatment, social, and psychological implications. Even more concerning is a rising trend of EO cancers in multiple tumor types. Research and investigation in EO cancers will help elucidate mechanisms of carcinogenesis, differences in biology and response to treatment, and the need for multidisciplinary care to ensure comprehensive treatment and support for young patients.

Case report: Complete response to pembrolizumab in a liver metastatic colon adenocarcinoma patient with a novel likely pathogenic germline MSH2 mutation

Lynch syndrome (LS) is a genetic disorder mainly caused by germline mutations in mismatched repair (MMR) genes (MSH2, MLH1, MSH6, and PMS2) or deletions of the epithelial cell adhesion molecule gene (EPCAM). A 43-year-old Chinese male patient underwent radical surgery and was pathologically confirmed to have stage IIIB colon adenocarcinoma. After four cycles of standard adjuvant chemotherapy, the tumor reoccurred in situ with intestinal obstruction. The patient received secondary colectomy. Immunohistochemistry analysis revealed a loss of MSH2 protein expression in the surgical specimen. Noticing that the patient's mother and grandfather all were diagnosed with LS-related cancers, we collected the patient's and his mother's peripheral blood for genetic testing, and the result showed a six-base deletion of MSH2. Thus, we concluded that our patient had LS. Subsequently, the patient accepted pembrolizumab as the first-line systemic therapy after liver metastases. He achieved clinical complete response (cCR) within 2 months and remained progression-free for more than 2 years. The case report showed that MSH2 mutation (c.489_494deTGGGTA) is a likely pathogenic mutation, and immunotherapy (pembrolizumab) is effective for this patient.

Oncology Informatics for Lynch Syndrome Research and Care: A Literature Review

PURPOSE

This study aims to review and evaluate available informatics platforms for research and management purposes of Lynch syndrome (LS) to identify gaps and needs for future development.

METHODS

LS informatics tools were identified through literature search in four publication databases (1 and Scopus). First, the LS and functional elements of every informatics tools for LS were introduced. Then, current existing LS informatics tools were reviewed and explained.

RESULTS

A detailed review of implemented studies shows that many types of informatics platforms are available for LS management (ie, prediction model, clinical decision support system, database website, and other tools for research and management purposes of LS). Moreover, several dimensions of existing LS informatics tools were discussed and features and positive findings were reported.

CONCLUSION

Reviewing the literature reveals that several LS informatics tools were focused on gene-specific estimate, cancer risk prediction, identifying/screening patients, supporting personalized care of individuals with LS, and storing mismatch repair mutations information. Nevertheless, these platforms do not fully cover the care and research purposes. For instance, future developments of LS tools require more attention to dynamic knowledgebase, extra-colonic lynch–related cancers on the basis of precision medicine, variants of unknown significance, and support from diagnosis to surveillance for patient follow-up. Insights and recommendations provided in this study could help researchers and developers to meet the existing challenges in future developments.

The Role of Immunohistochemistry Markers in Endometrial Cancer with Mismatch Repair Deficiency: A Systematic Review

The objective of this systematic review was to summarize our current knowledge of the role of immunohistochemistry (IHC) markers for identifying mismatch repair-deficient (MMRd) tumors in endometrial cancer (EC). Identification of MMRd tumors, which occur in 13% to 30% of all ECs, has become critical for patients with colorectal and endometrial cancer for therapeutic management, clinical decision making, and prognosis. This review was conducted by two authors applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the following terms: “immunohistochemistry and microsatellite instability endometrial cancer” or “immunohistochemistry and mismatch repair endometrial cancer” or “immunohistochemistry and mismatch repair deficient endometrial cancer”. Among 596 retrieved studies, 161 fulfilled the inclusion criteria. Articles were classified and presented according to their interest for the diagnosis, prognosis, and theragnostics for patients with MMRd EC. We identified 10, 18, and 96 articles using IHC expression of two, three, or four proteins of the MMR system (MLH1, MSH2, MHS6, and PMS2), respectively. MLH1 promoter methylation was analyzed in 57 articles. Thirty-four articles classified MMRd tumors with IHC markers according to their prognosis in terms of recurrence-free survival (RFS), overall survival (OS), stage, grade, and lymph node invasion. Theragnostics were studied in eight articles underlying the important concentration of PD-L1 in MMRd EC. Even though the role of IHC has been challenged, it represents the most common, robust, and cheapest method for diagnosing MMRd tumors in EC and is a valuable tool for exploring novel biotherapies and treatment modalities.

Exome sequencing revealed comparable frequencies of RNF43 and BRAF mutations in Middle Eastern colorectal cancer

Mutation-induced activation of Wnt-β Catenin signaling pathway is frequent in CRC. The E3 ubiquitin ligase, RNF43, has been reported to negatively regulate the Wnt signaling pathway and RNF43 mutations are frequently seen in CRC. However, its role in Middle Eastern CRC remains unclear. Therefore, we employed Exome and Sanger sequencing technology to assess the frequency of RNF43 mutations and its association with other clinico-pathological features in Middle Eastern CRC. RNF43 mutations were found in 5.9% (13/220) of CRC cases and was inversely correlated to APC and TP53 mutations. A strong association of RNF43 mutations with right sided and sporadic microsatellite instable (MSI) CRC was observed. No association was identified between RNF43 mutation and other clinico-pathological features including BRAF mutation, age, tumor histological subtype, tumor grade or patients’ prognosis. Multivariate logistic regression analysis revealed that MSI status and wild type APC were independent predictor of RNF43 mutation. We conclude that RNF43 mutations occur in Middle Eastern CRC at comparable frequencies with BRAF mutations and represent a distinct molecular subtype which further enhances our understanding of how different mutational subsets of Wnt tumor suppressor genes link to distinct tumor characteristics, which might be considered for treatment strategies for CRC patients.

Diagnosis and management of Lynch syndrome

Lynch syndrome (LS) is a dominantly inherited cancer susceptibility syndrome defined by presence of pathogenic variants in DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2, or in deletions of the EPCAM gene. Although LS is present in about 1 in 400 people in the UK, it estimated that only 5% of people with this condition are aware of the diagnosis. Therefore, testing for LS in all new diagnoses of colorectal or endometrial cancers is now recommended in the UK, and gastroenterologists can offer 'mainstreamed' genetic testing for LS to patients with cancer. Because LS results in a high lifetime risk of colorectal, endometrial, gastric, ovarian, hepatobiliary, brain and other cancers, the lifelong care of affected individuals and their families requires a coordinated multidisciplinary approach. Interventions such as high-quality 2-yearly colonoscopy, prophylactic gynaecological surgery, and aspirin are proven to prevent and facilitate early diagnosis and prevention of cancers in this population, and improve patient outcomes. Recently, an appreciation of the mechanism of carcinogenesis in LS-associated cancers has contributed to the development of novel therapeutic and diagnostic approaches, with a gene-specific approach to disease management, with potential cancer-preventing vaccines in development. An adaptive approach to surgical or oncological management of LS-related cancers may be considered, including an important role for novel checkpoint inhibitor immunotherapy in locally advanced or metastatic disease. Therefore, a personalised approach to lifelong gene-specific management for people with LS provides many opportunities for cancer prevention and treatment which we outline in this review.

Genetic Susceptibility to Endometrial Cancer: Risk Factors and Clinical Management

Endometrial cancer (EC) is the most common cancer affecting the female reproductive organs in higher-income states. Apart from reproductive factors and excess weight, genetic predisposition is increasingly recognized as a major factor in endometrial cancer risk. Endometrial cancer is genetically heterogeneous: while a subgroup of patients belongs to cancer predisposition syndromes (most notably the Lynch Syndrome) with high to intermediate lifetime risks, there are also several common genomic polymorphisms contributing to the spectrum of germline predispositions. Germline variants and somatic events may act in concert to modulate the molecular evolution of the tumor, where mismatch-repair deficiency is common in endometrioid endometrial tumors whereas homologous recombinational repair deficiency has been described for non-endometrioid endometrial tumors. In this review, we will survey the currently known genomic predispositions for endometrial cancer and discuss their relevance for clinical management in terms of counseling, screening and novel treatments.

Family history of colorectal cancer and survival: a Swedish population-based study

OBJECTIVES

A family history of colorectal cancer (CRC) is an established risk factor for developing CRC, whilst the impact of family history on prognosis is unclear. The present study assessed the association between family history and prognosis and, based on current evidence, explored whether this association was modified by age at diagnosis.

METHODS

Using data from the Swedish Colorectal Cancer Registry (SCRCR) linked with the Multigeneration Register and the National Cancer Register, we identified 31 801 patients with a CRC diagnosed between 2007 and 2016. The SCRCR is a clinically rich database which includes information on the cancer stage, grade, location, treatment, complications and postoperative follow-up.

RESULTS

We estimated excess mortality rate ratios (EMRR) for relative survival and hazard ratios (HR) for disease-free survival with 95% confidence intervals (CIs) using flexible parametric models. We found no association between family history and relative survival (EMRR = 0.96, 95% CIs: 0.89-1.03, P = 0.21) or disease-free survival (HR = 0.98, 95% CIs: 0.91-1.06, P = 0.64). However, age was found to modify the impact of family history on prognosis. Young patients (<50 at diagnosis) with a positive family history had less advanced (i.e. stages I and II) cancers than those with no family history (OR = 0.71, 95% CI: 0.56-0.89, P = 0.004) and lower excess mortality even after adjusting for cancer stage (EMMR = 0.63, 95% CIs: 0.47-0.84, P = 0.002).

CONCLUSIONS

Our results suggest that young individuals with a family history of CRC may have greater health awareness, attend opportunistic screening and adopt lifestyle changes, leading to earlier diagnosis and better prognosis.

The effect of using fecal testing after a negative sigmoidoscopy on the risk of death from colorectal cancer

OBJECTIVE

To examine whether receiving a fecal occult blood test after a negative sigmoidoscopy reduced mortality from colorectal cancer.

METHODS

We used a nested case-control design with incidence-density matching in historical cohorts of 1,877,740 50-90-year-old persons during 2006-2012, in an integrated health-system setting. We selected 1758 average risk patients who died from colorectal cancer and 3503 matched colorectal cancer-free persons. Colorectal cancer-specific death was ascertained from cancer and mortality registries. Screening histories were determined from electronic and chart-audit clinical data in the 5- to 10-year period prior to the reference date. We evaluated receipt of subsequent fecal occult blood test within five years of the reference date among patients with negative sigmoidoscopy two to six years before the reference date.

RESULTS

Of the 5261 patients, 831 patients (204 colorectal cancer deaths/627 controls) had either negative sigmoidoscopy only (n = 592) or negative sigmoidoscopy with subsequent screening fecal occult blood test (n = 239). Fifty-six (27.5%) of the 204 patients dying of colorectal cancer and 183 (29.2%) of the 627 colorectal cancer-free patients received fecal occult blood test following a negative sigmoidoscopy. Conditional regressions found no significant association between fecal occult blood test receipt and colorectal cancer death risk, overall (adjusted odds ratio = 0.93, confidence interval: 0.65-1.33), or for right (odds ratio = 1.02, confidence interval: 0.65-1.60) or left-colon/rectum (odds ratio = 0.77, confidence interval: 0.39-1.52) cancers. Similar results were obtained in sensitivity analyses with alternative exposure ascertainment windows or timing of fecal occult blood test.

CONCLUSIONS

Our results suggest that receipt of at least one fecal occult blood test during the several years after a negative sigmoidoscopy did not substantially reduce mortality from colorectal cancer.

Effectiveness of screening colonoscopy in reducing the risk of death from right and left colon cancer: a large community-based study

OBJECTIVE

Screening colonoscopy's effectiveness in reducing colorectal cancer mortality risk in community populations is unclear, particularly for right-colon cancers, leading to recommendations against its use for screening in some countries. This study aimed to determine whether, among average-risk people, receipt of screening colonoscopy reduces the risk of dying from both right-colon and left-colon/rectal cancers.

DESIGN

We conducted a nested case-control study with incidence-density matching in screening-eligible Kaiser Permanente members. Patients who were 55-90 years old on their colorectal cancer death date during 2006-2012 were matched on diagnosis (reference) date to controls on age, sex, health plan enrolment duration and geographical region. We excluded patients at increased colorectal cancer risk, or with prior colorectal cancer diagnosis or colectomy. The association between screening colonoscopy receipt in the 10-year period before the reference date and colorectal cancer death risk was evaluated while accounting for other screening exposures.

RESULTS

We analysed 1747 patients who died from colorectal cancer and 3460 colorectal cancer-free controls. Compared with no endoscopic screening, receipt of a screening colonoscopy was associated with a 67% reduction in the risk of death from any colorectal cancer (adjusted OR (aOR)=0.33, 95% CI 0.21 to 0.52). By cancer location, screening colonoscopy was associated with a 65% reduction in risk of death for right-colon cancers (aOR=0.35, CI 0.18 to 0.65) and a 75% reduction for left-colon/rectal cancers (aOR=0.25, CI 0.12 to 0.53).

CONCLUSIONS

Screening colonoscopy was associated with a substantial and comparably decreased mortality risk for both right-sided and left-sided cancers within a large community-based population.

Association of a novel point mutation in MSH2 gene with familial multiple primary cancers

Background

Multiple primary cancers (MPC) have been identified as two or more cancers without any subordinate relationship that occur either simultaneously or metachronously in the same or different organs of an individual. Lynch syndrome is an autosomal dominant genetic disorder that increases the risk of many types of cancers. Lynch syndrome patients who suffer more than two cancers can also be considered as MPC; patients of this kind provide unique resources to learn how genetic mutation causes MPC in different tissues.

Methods

We performed a whole genome sequencing on blood cells and two tumor samples of a Lynch syndrome patient who was diagnosed with five primary cancers. The mutational landscape of the tumors, including somatic point mutations and copy number alternations, was characterized. We also compared Lynch syndrome with sporadic cancers and proposed a model to illustrate the mutational process by which Lynch syndrome progresses to MPC.

Results

We revealed a novel pathologic mutation on the MSH2 gene (G504 splicing) that associates with Lynch syndrome. Systematical comparison of the mutation landscape revealed that multiple cancers in the proband were evolutionarily independent. Integrative analysis showed that truncating mutations of DNA mismatch repair (MMR) genes were significantly enriched in the patient. A mutation progress model that included germline mutations of MMR genes, double hits of MMR system, mutations in tissue-specific driver genes, and rapid accumulation of additional passenger mutations was proposed to illustrate how MPC occurs in Lynch syndrome patients.

Conclusion

Our findings demonstrate that both germline and somatic alterations are driving forces of carcinogenesis, which may resolve the carcinogenic theory of Lynch syndrome.

Electronic supplementary material

The online version of this article (10.1186/s13045-017-0523-y) contains supplementary material, which is available to authorized users.

Thyroid cancer in a patient with Lynch syndrome - case report and literature review

Lynch syndrome describes a familial cancer syndrome comprising germline mutations in one of four DNA mismatch repair genes, MLH1, MSH2, MSH6, and PMS2 and is characterized by colorectal, endometrial, and other epithelial malignancies. Thyroid cancer is not usually considered to be part of the constellation of Lynch syndrome cancers nor have Lynch syndrome tumor gene mutations been reported in thyroid malignancies. This study reports a woman with Lynch syndrome (colonic cancer and a DNA mismatch repair mutation in the MSH2 gene) with a synchronous papillary thyroid cancer. Six years later, she developed metachronous breast cancer. Metastatic bone disease developed after 3 years, and the disease burden was due to both breast and thyroid diseases. Despite multiple interventions for both metastatic breast and thyroid diseases, the patient’s metastatic burden progressed and she died of leptomeningeal metastatic disease. Two prior case reports suggested thyroid cancer may be an extraintestinal malignancy of the Lynch syndrome cancer group. Hence, this study examined the genetic relationship between the patient’s known Lynch syndrome and her thyroid cancer. The thyroid cancer tissue showed normal expression of MSH2, suggesting that the tumor was not due to the oncogenic mutation of Lynch syndrome, and molecular analysis confirmed BRAF V600E mutation. Although in this case the thyroid cancer was sporadic, it raises the importance of considering cancer genetics in familial cancer syndromes when other cancers do not fit the criteria of the syndrome. Careful documentation of other malignancies in patients with thyroid cancer and their families would assist in better understanding of any potential association. Appropriate genetic testing will clarify whether a common pathogenic mechanism links seemingly unrelated cancers.

Rectal Carcinoma: Demographics and Clinicopathological Features from Pakistani Population Perspective

Background

Colorectal carcinoma is ranked as the second most common cancer diagnosis in females and third in males. It is the third leading cause of cancer-related deaths worldwide. Disease burden has been attributed to a myriad of factors comprising genetic, environmental, and dietary factors. Rectal cancer has been shown to demonstrate variance according to the geographical location.

Methods

A retrospective review of 477 rectal cancer patients treated at Shaukat Khanum Memorial Cancer Hospital & Research Centre from 2006 to 2014 was performed. Demographic and clinicopathological features were compared between the two age groups (≤40 or >40 years). These included sex, ethnicity, family history of cancer, the location of tumor, clinical staging, histopathological type, and response to chemoradiation. Chi-square was used to compare the frequencies between the two age groups. p-value < 0.05 was taken as significant.

Results

Mean age of the study group was 44.62 ± 16.11 years. 43.8% were ≤40 years of age, and 70.2% were male. 50.3% patients belong to Punjab province, 287 (60.2%) had lower rectal cancer, family history of cancer was present in 82 (17.2%) patients. 432 (90.5%) patients had T1/T2 disease and 296 (62.1%) had N2 disease. Metastatic disease at presentation was observed in 37 (7.8%). Progressive disease was found in 90 (18%) patients.

Conclusion

High frequency of young onset rectal cancers and the lack of family history emphasize the need of indigenous strategies and national awareness of this disease for an early identification of these patients.

Genetic mutation risk calculation in Lynch syndrome inheritance: Evaluating the utility of the PREMM1,2,6 model in Lyon: The first French study

Lynch syndrome is due to germline mutations in mismatch repair genes: MLH1, MSH2, MSH6 and PMS2. It is characterized by an increased risk of various cancers including colorectal and endometrial cancers. Early diagnosis of these patients allows for appropriate surveillance and improves survival rates. Differentiating between patients who should undergo genetic testing and those for whom it is not necessary is difficult despite various established criteria (Amsterdam and Bethesda). Often, health professionals meet in multidisciplinary committees (MDC) to discuss patient cases regarding Lynch syndrome. In this study, we evaluated if the prediction model PREMM_1,2,6 could be used to enhance MDC decision-making and whether it should be included in our own routine practice and in those of other French teams. Using the prediction model in our cohort would have avoided 12% of the analyses recommended by our MDC. Furthermore, all patients with a mutation in one of the MMR genes would have been detected. In addition, according to the model, we should have provided 20% more genetic testing, which suggests that the decision-making criteria used by the professionals in our MDC, was too restrictive. These results suggest that PREMM_1,2,6 should be used in current practice to validate the decisions of the MDC before genetic testing is performed in complex cases. The model should be added as a major quality criterion for genetic testing, along with somatic tests, as previously reported in the literature.

Efficient screening strategy for Lynch syndrome in Japanese endometrial cancer

Lynch syndrome (LS) is an inherited disorder caused by a germline mutation in the DNA mismatch repair (MMR) genes and is associated with increased risk of various cancers, particularly colorectal cancer and endometrial cancer (EC). It is significant to identify LS in EC patients for prediction and prevention of the succeeding other associated cancers. However, useful LS screening guidelines for EC have not been established. The purpose of our study is to devise an efficient and practical screening strategy for LS in EC. We designed original criteria, named "APF criteria," with lenient terms (Age of onset < 50, or Personal or Family history of associated cancers) and applied it to unselected EC patients. We performed immunohistochemistry (IHC) and the methylation assay of MutL homolog 1 (MLH1) gene promoter using the tumors of patients who met our criteria, and thus selected "suspected LS" as the candidates for genetic analyses. Of 360 EC patients, 187 (51.9%) met the APF criteria, and the tumor specimens were available from 182 out of the 187 patients. IHC revealed that expression of at least one MMR protein was absent in cell nuclei of 54 (29.6%) tumors. Of 20 tumors lacking MLH1 protein expression, 14 cases were judged sporadic EC because of the hypermethylated MLH1 promoter. We thus selected 40 (11.1%) of 360 EC patients as "suspected LS." Our strategy that consists of clinical triage and the molecular analyses is expected to improve the screening efficiency and reduce the cost of LS identification in EC.

Observational methods to assess the effectiveness of screening colonoscopy in reducing right colon cancer mortality risk: SCOLAR

AIMS

Screening colonoscopy's effectiveness in reducing risk of death from right colon cancers remains unclear. Methodological challenges of existing observational studies addressing this issue motivated the design of 'Effectiveness of Screening for Colorectal Cancer in Average-Risk Adults (SCOLAR)'.

METHODS

SCOLAR is a nested case-control study based on two large integrated health systems. This affords access to a large, well-defined historical cohort linked to integrated data on cancer outcomes, patient eligibility, test indications and important confounders.

RESULTS

We found electronic data adequate for excluding ineligible patients (except family history), but not the detailed information needed for test indication assignment.

CONCLUSION

The lessons of SCOLAR's design and implementation may be useful for future studies seeking to evaluate the effectiveness of screening tests in community settings.

hMLH1 promoter methylation and BRAF mutations in high-frequency microsatellite instability colorectal cancers not fulfilling the revised Bethesda guidelines

PURPOSE

Sporadic colorectal cancers with high-frequency microsatellite instability (MSI-H) are related to hypermethylation of mismatch repair (MMR) genes and a higher frequency of BRAF mutations than Lynch syndrome. We estimated the feasibility of hereditary colorectal cancer based on hMLH1 methylation and BRAF mutations.

METHODS

Between May 2005 and June 2011, we enrolled all 33 analyzed patients with MSI-H cancer (male:female, 23:10; mean age, 65.5 ± 9.4 years) from a prospectively maintained database that didn't match Bethesda guidelines and who had results of hMLH1 methylation and BRAF mutations.

RESULTS

Among the 33 patients, hMLH1 promoter methylation was observed in 36.4% (n = 12), and was not significantly related with clinicopathologic variables, including MLH1 expression. BRAF mutations were observed in 33.3% of the patients (n = 11). Four of 11 and five of 22 patients with MSI-H colon cancers were BRAF mutation (+)/hMLH1 promoter methylation (-) or BRAF mutation (-)/hMLH1 promoter methylation (+). Of the 33 patients, 21.2% were BRAF mutation (+)/hMLH1 promoter methylation (+), indicating sporadic cancers. Seventeen patients (51.5%) were BRAF mutation (-)/hMLH1 promoter methylation (-), and suggested Lynch syndrome.

CONCLUSION

Patients with MSI-H colorectal cancers not fulfilling the Bethesda guidelines possibly have hereditary colorectal cancers. Adding tests of hMLH1 promoter methylation and BRAF mutations can be useful to distinguish them from sporadic colorectal cancers.

Prevalence of germline MUTYH mutations among Lynch-like syndrome patients

BACKGROUND AND AIMS

Individuals with tumours showing mismatch repair (MMR) deficiency not linked to germline mutations or somatic methylation of MMR genes have been recently referred as having 'Lynch-like syndrome' (LLS). The genetic basis of these LLS cases is unknown. MUTYH-associated polyposis patients show some phenotypic similarities to Lynch syndrome patients. The aim of this study was to investigate the prevalence of germline MUTYH mutations in a large series of LLS patients.

METHODS

Two hundred and twenty-five probands fulfilling LLS criteria were included in this study. Screening of MUTYH recurrent mutations, whole coding sequencing and a large rearrangement analysis were undertaken. Age, sex, clinical, pathological and molecular characteristics of tumours including KRAS mutations were assessed.

RESULTS

We found a prevalence of 3.1% of MAP syndrome in the whole series of LLS (7/225) and 3.9% when only cases fulfilling clinical criteria were considered (7/178). Patients with MUTYH biallelic mutations had more adenomas than monoallelic (P=0.02) and wildtype patients (P<0.0001). Six out of nine analysed tumours from six biallelic MUTYH carriers harboured KRAS-p.G12C mutation. This mutation was found to be associated with biallelic MUTYH germline mutation when compared with reported series of unselected colorectal cancer cohorts (P<0.0001).

CONCLUSIONS

A proportion of unexplained LLS cases is caused by biallelic MUTYH mutations. The obtained results further justify the inclusion of MUTYH in the diagnostic strategy for Lynch syndrome-suspected patients.

Prediction models in Lynch syndrome

Prediction models for the identification of Lynch syndrome have been developed to quantify an individual's risk of carrying a mismatch repair gene mutation and help clinicians decide for whom further risk assessment and genetic testing is necessary. There are diverse clinical settings in which a healthcare provider has the opportunity to assess an individual for Lynch syndrome. Prediction models offer a potentially feasible and useful strategy to systematically identify at-risk individuals, whether they are affected with colorectal cancer or not, and to help with management of the implications of molecular and germline test results. Given the complexity of diagnostic information currently available to clinicians involved in identifying and caring for patients with Lynch syndrome, prediction models provide a useful and complementary aid in medical decision-making. Systematic implementation of prediction models estimates should be considered in routine clinical care and at various stages of cancer risk assessment and prevention. In this manuscript, we review the main prediction models developed for Lynch syndrome, focus on their specific features and performance assessed in several validation studies, compare the models with other clinical and molecular strategies for the diagnosis of Lynch syndrome, and discuss their potential uses in clinical practice.

Development of multidisciplinary committees for decision making and care management in hereditary colon cancer: the French state of the art

Multidisciplinary Committees (MDC) in France were established by the Institut National du Cancer for the management of therapeutic cancer treatment. We wanted to know if this approach is being utilized in Cancer Genetics, in particular for patients with a digestive cancer predisposition. A questionnaire was sent to the 33 French oncogenetic centers. Responses were received from all clinics. We found that 76 % of centers regularly use MDCs for the management of hereditary digestive cancers. Familial colon cancer cases were the most common situation, in which MDCs were utilized. Participation of various medical specialists was reported as follows: geneticists (100 %), gastroenterologists (76 %), genetic counselors (84 %), surgeons (32 %), and biologists (36 %). Twenty percent of centers consult MDCs for every patient compared to 80 % of centers that use MDCs only for select cases. MDCs represent a multidisciplinary approach for patients affected by inherited cancers and may optimize follow-up for genetic screening and further care management.

Criteria and prediction models for mismatch repair gene mutations: a review

One of the strongest predictors of colorectal cancer risk is carrying a germline mutation in a DNA mismatch repair (MMR) gene. Once identified, mutation carriers can be recommended for intensive screening that will substantially reduce their high colorectal cancer risk. Conversely, the relatives of carriers identified as non-carriers can be relieved of the burden of intensive screening. Criteria and prediction models that identify likely mutation carriers are needed for cost-effective, targeted, germline testing for MMR gene mutation. We reviewed 12 criteria/guidelines and 8 prediction models (Leiden, Amsterdam-plus, Amsterdam-alternative, MMRpro, PREMM1,2,6, MMRpredict, Associazione Italiana per lo studio della Familiarità ed Ereditarietà dei tumori Gastrointestinali (AIFEG) and the Myriad Genetics Prevalence table) for identifying mutation carriers. While criteria are only used to identify individuals with colorectal cancer (yes/no for screening followed by germline testing), all prediction models except MMRpredict and Myriad tables can predict the probability of carrying mutations for individuals with or without colorectal cancer. We conducted a meta-analysis of the discrimination performance of 17 studies that validated the prediction models. The pooled estimate for the area under curve was 0.80 (95% CI 0.72 to 0.88) for MMRpro, 0.81 (95% CI 0.73 to 0.88) for MMRpredict, 0.84 (95% CI 0.81 to 0.88) for PREMM, and 0.85 (95% CI 0.78 to 0.91) for Leiden model. Given the high degree of overlap in the CIs, we cannot state that one model has a higher discrimination than any of the others. Overall, the existing statistical models have been shown to be sensitive and specific (at a 5% cut-off) in predicting MMR gene mutation carriers. Future models may need to: provide prediction of PMS2 mutations, take into account a wider range of Lynch syndrome-associated cancers when assessing family history, and be applicable to all people irrespective of any cancer diagnosis.

Analysis of colorectal cancers in British Bangladeshi identifies early onset, frequent mucinous histotype and a high prevalence of RBFOX1 deletion

Background

Prevalence of colorectal cancer (CRC) in the British Bangladeshi population (BAN) is low compared to British Caucasians (CAU). Genetic background may influence mutations and disease features.

Methods

We characterized the clinicopathological features of BAN CRCs and interrogated their genomes using mutation profiling and high-density single nucleotide polymorphism (SNP) arrays and compared findings to CAU CRCs.

Results

Age of onset of BAN CRC was significantly lower than for CAU patients (p=3.0 x 10^-5) and this difference was not due to Lynch syndrome or the polyposis syndromes. KRAS mutations in BAN microsatellite stable (MSS) CRCs were comparatively rare (5.4%) compared to CAU MSS CRCs (25%; p=0.04), which correlates with the high percentage of mucinous histotype observed (31%) in the BAN samples. No BRAF mutations was seen in our BAN MSS CRCs (CAU CRCs, 12%; p=0.08). Array data revealed similar patterns of gains (chromosome 7 and 8q), losses (8p, 17p and 18q) and LOH (4q, 17p and 18q) in BAN and CAU CRCs. A small deletion on chromosome 16p13.2 involving the alternative splicing factor RBFOX1 only was found in significantly more BAN (50%) than CAU CRCs (15%) cases (p=0.04). Focal deletions targeting the 5’ end of the gene were also identified. Novel RBFOX1 mutations were found in CRC cell lines and tumours; mRNA and protein expression was reduced in tumours.

Conclusions

KRAS mutations were rare in BAN MSS CRC and a mucinous histotype common. Loss of RBFOX1 may explain the anomalous splicing activity associated with CRC.

The hMSH2(M688R) Lynch syndrome mutation may function as a dominant negative

The hMSH2(M688R) mismatch repair (MMR) gene mutation has been found in five large families from Tenerife, Spain, suggesting it is a Lynch syndrome or hereditary non-polyposis colorectal cancer (LS/HNPCC) founder mutation. In addition to classical LS/HNPCC tumors, these families present with a high incidence of central nervous system (CNS) tumors normally associated with Turcot or constitutional mismatch repair deficiency (CMMR-D) syndromes. Turcot and CMMR-D mutations may be biallelic, knocking out both copies of the MMR gene. The hMSH2(M688R) mutation is located in the ATP hydrolysis (ATPase) domain. We show that the hMSH2(M688R)-hMSH6 heterodimer binds to mismatched nucleotides but lacks normal ATP functions and inhibits MMR in vitro when mixed with the wild-type (WT) heterodimer. Another alteration that has been associated with LS/HNPCC, hMSH2(M688I)-hMSH6, displays no identifiable differences with the WT heterodimer. Interestingly, some extracolonic tumors from hMSH2(M688R) carriers may express hMSH2-hMSH6, yet display microsatellite instability (MSI). The functional analysis along with variability in tumor expression and the high incidence of CNS tumors suggests that hMSH2(M688R) may act as a dominant negative in some tissues, while the hMSH2(M688I) is most likely a benign polymorphism.

Tumor spectrum in lynch syndrome, DNA mismatch repair system and endogenous carcinogens

Inactivation of Mismatch Repair genes in Lynch Syndrome, caused by inherited mutations, decreases the ability to repair DNA errors throughout life. This deficit may allow the development of any tumor type. Nevertheless, the Syndrome develops a specific tumor spectrum associated with the disease. We think that such spectrum of tumors would be related to the action of certain endogenous carcinogens such as bile acids and estrogens that aggravate the inherited defect.

Yield of routine molecular analyses in colorectal cancer patients ≤70 years to detect underlying Lynch syndrome

Although early detection of Lynch syndrome (LS) is important, a considerable proportion of patients with LS remains unrecognized. We aimed to study the yield of LS detection by routine molecular analyses in colorectal cancer (CRC) patients until 70 years of age. We prospectively included consecutive CRC patients ≤70 years. Tumour specimens were analysed for microsatellite instability (MSI), immunohistochemical mismatch-repair protein expression and MLH1-promoter methylation. Tumours were classified as either: (a) likely caused by LS; (b) sporadic microsatellite-unstable (MSI-H); or (c) microsatellite-stable (MSS). Predictors of LS were determined by multivariable logistic regression. A total of 1117 CRC patients (57% males, median age 61 years) were included. Fifty patients (4.5%, 95% CI 3.4-5.9) were likely to have LS, and 71 had a sporadic MSI-H tumour (6.4%, 95% CI 5.1-8.0). Thirty-five patients likely to have LS (70%) were aged > 50 years. A molecular profile compatible with LS was detected in 10% (15/144) of patients aged ≤50, in 4% (15/377) of those aged 51-60 and in 3% (20/596) of patients > 61 years. Compared to MSS cases, patients likely to have LS were significantly younger (OR 3.9, 95% CI 1.7-8.7) and more often had right-sided CRCs (OR 14, 95% CI 6.0-34). In conclusion, molecular screening for LS in CRC patients ≤70 years leads to identification of a molecular profile compatible with LS in 4.5% of patients, with most of them not fulfilling the age criterion (≤50 years) routinely used for LS assessment. Routine use of MSI testing may be considered in CRC patients up to the age of 70 years, with a central role for the pathologist in the selection of patients.

Hereditary colon cancer syndromes

Colon cancer is associated with a family history in up to 25% of cases. As many as 5% are associated with an established hereditary syndrome, demonstrating the profound influence of inheritable genetic mechanisms in the development of this disease. These syndromes confer a diverse spectrum of risk, age of presentation, endoscopic and histological findings, extracolonic manifestations, and modes of inheritance. As the molecular characteristics of these disorders become better described, enhanced genotype-phenotype correlations may offer a more targeted approach to diagnosis, screening, and surveillance. While the strategies for diagnosis and management of familial adenomatous polyposis (FAP) and Lynch syndrome are more established, the approach to newly recognized syndromes such as MUTYH-associated polyposis (MAP) and hyperplastic polyposis syndromes continues to evolve. Effective cancer prevention in affected individuals and at-risk family members first requires timely recognition of these hereditary colon cancer syndromes followed by integration of genetic testing and clinical examinations.

Evidence of linkage to chromosomes 10p15.3-p15.1, 14q24.3-q31.1 and 9q33.3-q34.3 in non-syndromic colorectal cancer families

Up to 25% of colorectal cancer (CRC) may be caused by inherited genetic variants that have yet to be identified. Previous genome-wide linkage studies (GWLSs) have identified a new loci postulated to contain novel CRC risk genes amongst affected families carrying no identifiable mutations in any of the known susceptibility genes for familial CRC syndromes. To undertake a new GWLS, we recruited members from 54 non-syndromic families from Australia and Spain where at least two first-degree relatives were affected by CRC. We used single-nucleotide polymorphism arrays to genotype 98 concordant affected relative pairs that were informative for linkage analyses. We tested for genome-wide significance (GWS) for linkage to CRC using a quantile statistic method, and we found that GWS was achieved at the 5% level. Independently, using the PSEUDO gene-dropping algorithm, we also found that GWS for linkage to CRC was achieved (P=0.02). Merlin non-parametric linkage analysis revealed significant linkage to CRC for chromosomal region 10p15.3-p15.1 and suggestive linkage to CRC for regions on 14q and 9q. The 10p15.3-p15.1 has not been reported to be linked to hereditary CRC in previous linkage studies, but this region does harbour the Kruppel-like factor 6 (KLF6) gene that is known to be altered in common CRC. Further studies aimed at localising the responsible genes, and characterising their function will give insight into the factors responsible for susceptibility in such families, and perhaps shed further light on the mechanisms of CRC development.

Testing women with endometrial cancer to detect Lynch syndrome

PURPOSE

Women with endometrial cancer as a result of Lynch syndrome may not be identified as such by Amsterdam II criteria. We estimated the costs and benefits of different testing criteria to identify Lynch syndrome in women with endometrial cancer.

METHODS

We developed a Markov Monte Carlo simulation model to compare six criteria for Lynch syndrome testing for women with endometrial cancer: Amsterdam II criteria; age younger than 50 years with at least one first-degree relative having a Lynch-associated cancer at any age (FDR); immunohistochemistry (IHC) triage if age younger than 50 years; IHC triage if age younger than 60 years; IHC triage at any age if 1 FDR; and IHC triage of all endometrial cancers. Net health benefit was life expectancy, and primary outcome was the incremental cost-effectiveness ratio (ICER). The model estimated the number of new colorectal cancers associated with each strategy.

RESULTS

IHC triage of women with endometrial cancer having at least 1 FDR yielded a favorable ICER of $9,126 per year of life gained. This strategy would subject fewer cases to IHC but identify more mutation carriers than age thresholds of 50 or 60 years. IHC triage of all endometrial cancers could identify the most mutation carriers and prevent the most colorectal cancers but at considerable cost ($648,494 per year of life gained).

CONCLUSION

IHC triage of women with endometrial cancer at any age having at least 1 FDR with a Lynch-associated cancer is a cost-effective strategy for detecting Lynch syndrome.

Lynch syndrome in Tunisia: first description of clinical features and germline mutations

PURPOSE

High rates of early colorectal cancers (CRC) are observed in Tunisia suggesting genetic susceptibility. Nevertheless, up to now, no molecular study has been performed in the Tunisian population. In our research, we evaluated the clinical characteristics of Tunisian families suspected of Lynch syndrome and the contribution of DNA mismatch repair (MMR) genes.

METHODS

Thirty-one unrelated families suspected of Lynch syndrome were studied. Probands were tested for the presence of germline mutations in the MMR genes MLH1, MSH2, MSH6 and in MUTYH. Available tumours were analysed for microsatellite instability and expression of MMR proteins. Detailed family and medical histories were collected.

RESULTS

A total of 134 cancers were noted in the 31 families, the most frequent type of cancer corresponding to CRC (69%), followed by uterine cancer (7.5%). Germline mutations were identified in 11 (35.5%) families (six MSH2, five MLH1, including seven novel mutations), seven of which fulfilled the Amsterdam criteria (sensitivity, 63.6%; positive predictive value, 58.3%). Noteworthy, germline mutations were detected in 52.6% of male patients tested, but in only 8.3% of females (p = 0.02). Moreover, CRC were essentially left sided in families without detected mutation (p = 0.017). Ages of onset of cancers and tumour spectrum were very similar in families with or without MMR germline mutation, contrasting with previous studies performed in other populations.

CONCLUSIONS

MMR genes contribute significantly to CRC susceptibility in the Tunisian population. However, the cause of early CRC susceptibility remains unknown in most cases, especially in women and in patients with early left colon or rectal cancer.

"The cancer bond": exploring the formation of cancer risk perception in families with Lynch syndrome

This study explores the social context of hereditary cancer risk perception in three families, an African-American family, a Mexican-American family, and a Caucasian family, each with Lynch Syndrome documented by a mismatch repair gene mutation. Communication network assessments measured family communication about cancer experiences and genetic testing information among a total of 26 participants. Participant narratives were evaluated to gain insight into how family cancer experiences and genetic testing information have shaped perceptions of cancer risk. Analysis of communication networks indicated that some families discussed cancer experiences to a greater extent than genetic testing information, and vice-versa. Interviews elucidated that sharing both types of health information led participants to conceptualize linkages among a strong family history of cancer, genetic testing information, and cancer prevention strategies. Understanding how different types of family communication influence the formation of perceived hereditary disease risk may enhance efforts to tailor genetic counseling services for families.

Germline mutation analysis of hPMS2 gene in Chinese families with hereditary nonpolyposis colorectal cancer

AIM: To study the germline mutation of hPMS2 gene in 26 unrelated Chinese hereditary nonpolyposis colorectal cancer (HNPCC) probands and to fulfill the screening strategy for HNPCC in Chinese.

METHODS: Genomic DNA was extracted from the peripheral blood. To avoid the interference of pseudogene in detection of the remaining 11 exons (exon 1-5, 9, 11-15), long-range polymerase chain reaction (PCR) was conducted to amplify the complete coding region of hPMS2 gene firstly. Then 1/8 of the PCR products were used as template to amplify the individual exon respectively and DNA sequencing was done. Direct DNA sequencing of the conventional PCR products of exon 6, 7, 8 and 10 of hPMS2 gene was performed. The same analysis was made in 130 healthy persons without family histories of HNPCC to further investigate the pathological effects of the detected missense mutation.

RESULTS: One HNPCC proband fulfilled Bethesda guidelines and was found to carry the germline mutation of hPMS2 gene, which has not been reported in Chinese HNPCC families. It was a missense mutation at c.1532C>T of exon 11. It was detected in three controls as well with an occurrence rate of 2.3% (3/130). Since it could not be found in the PMS2-single nucleotide polymorphism (SNP) database, this missense mutation is a new SNP unreported up to date. Meanwhile, 260 reported SNPs of hPMS2 gene were detected in the 26 HNPCC probands. The 2nd and 5th exons were probably the hot SNP regions of hPMS2 gene in Chinese HNPCC families involving 53.1% of all reported SNP.

CONCLUSION: The germline mutation of hPMS2 gene may be rare in Chinese HNPCC families. The 2nd and 5th exons are hot SNP regions of hPMS2 gene.

MTHFR C677T and A1298C variant genotypes and the risk of microsatellite instability among Iranian colorectal cancer patients

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the folate metabolic pathway. We aimed to test the hypothesis that C677T and A1298C variants of MTHFR predispose to microsatellite instable (MSI) colorectal cancer. We determined MTHFR genotypes in 175 sporadic colorectal cancer patients and a total of 231 normal controls in Shiraz, Southern Iran. Among the genotypes found in our samples, MTHFR CT and CT+TT were associated with increased risk for CRC incidence [odds ratio (OR)=2.4, 95% confidence interval (95%CI)=1.8-4.4; OR=2.4, 95%CI=1.6-3.6, respectively]. Double heterozygotes 677CT/1298AC and double homozygote 677TT/1298AA and 677CC/1298CC genotypes also showed a significantly increased risk of developing CRC compared with the wild-type 677CC/1298AA genotypes of the controls. Among the 151 tumors tested, 36 (23.8%) were MSI+. MSI was more common in proximal tumors (OR=10.4; 95%CI=3.9-27.8) and in smokers (OR=2.9; 95%CI=1.3-6.7). In a case-control comparison, the MTHFR 677CT+TT genotype was strongly associated with MSI (OR=2.6; 95%CI=1.3-5.3). Hypermethylation of mismatch repair genes was positively related with MSI incidence in these tumor series (P=0.00). Our data suggest that the MTHFR 677CT+TT variant genotype may be a risk factor for MSI+ cancer.

Health and lifestyle behaviors among persons at risk of Lynch syndrome

OBJECTIVE

The aim of this study was to evaluate health behaviors among patients with colorectal cancer (CRC) and their at-risk relatives prior to undergoing genetic counseling and testing for Lynch syndrome and to examine associations between health risk behaviors and specific demographic and psychological variables.

METHODS

Participants included patients with CRC (n = 319) and their cancer-unaffected relatives (n = 110) who were enrolled in studies regarding Lynch syndrome genetic testing. Prior to undergoing genetic counseling or testing, participants completed a questionnaire including measures of demographic characteristics, health behaviors, cancer screening practices (Pap test, clinical breast exam, and mammogram), and psychological distress.

RESULTS

Unaffected participants scored higher on a risk behavior index (RBI) than patients with CRC (1.7 (SD = 1.0) vs. 1.4 (SD = .09); p < .01). All female participants underwent cancer screening at rates similar to national data. Higher RBI scores were associated with being male, having less education, and age less than 50-years.

CONCLUSIONS

We identified several health behaviors for potential intervention, including smoking, alcohol use, and diet. Genetic counseling offers a promising avenue for education and risk behavior reduction in persons at increased risk for cancer due to a familial or genetic predisposition, and a teachable moment to introduce lifestyle modifications.

The identification of colon cancer susceptibility genes by using genome-wide scans

Recent studies have indicated that in approximately 35% of all colorectal cancer (CRC) cases, the CRC was inherited. Although a number of high-risk familial variants have been identified, these mutations explain <6% of CRC cases; therefore, further genome-wide scans will need to be conducted in the future. There are two popular approaches to genome-wide scans, namely linkage and association. The linkage approach utilizes several hundred markers (typically between 300 and 500 markers) throughout the genome and identifies candidate regions shared among affected family members. Candidate regions are then scrutinized for the presence of susceptibility loci. Linkage studies require no prior information and can provide new avenues for future research, but the regions identified are often large and include many candidate genes. The second and more recent approach is the genome-wide association study (GWAS) in which hundreds of thousands of markers called single nucleotide polymorphisms (SNPs) are used to identify the SNPs associated with traits of interest by employing family-based or case-control association methods. GWAS studies require no prior information and, because they use hundreds of thousands of SNPs, they can target specific candidate genes and/or narrow regions for investigation. Study design considerations, methodology, and the execution of linkage and genome-wide association studies that use both family and case-control designs are covered in this chapter.

Are prediction models for Lynch syndrome valid for probands with endometrial cancer?

Currently, three prediction models are used to predict a patient's risk of having Lynch syndrome (LS). These models have been validated in probands with colorectal cancer (CRC), but not in probands presenting with endometrial cancer (EMC). Thus, the aim was to determine the performance of these prediction models in women with LS presenting with EMC. Probands with EMC and LS were identified. Personal and family history was entered into three prediction models, PREMM(1,2), MMRpro, and MMRpredict. Probabilities of mutations in the mismatch repair genes were recorded. Accurate prediction was defined as a model predicting at least a 5% chance of a proband carrying a mutation. From 562 patients prospectively enrolled in a clinical trial of patients with EMC, 13 (2.2%) were shown to have LS. Nine patients had a mutation in MSH6, three in MSH2, and one in MLH1. MMRpro predicted that 3 of 9 patients with an MSH6, 3 of 3 with an MSH2, and 1 of 1 patient with an MLH1 mutation could have LS. For MMRpredict, EMC coded as "proximal CRC" predicted 5 of 5, and as "distal CRC" three of five. PREMM(1,2) predicted that 4 of 4 with an MLH1 or MSH2 could have LS. Prediction of LS in probands presenting with EMC using current models for probands with CRC works reasonably well. Further studies are needed to develop models that include questions specific to patients with EMC with a greater age range, as well as placing increased emphasis on prediction of LS in probands with MSH6 mutations.

Hereditary non-polyposis colorectal cancer or Lynch syndrome: the gynaecological perspective

PURPOSE OF REVIEW

Hereditary non-polyposis colorectal cancer (HNPCC) or Lynch syndrome is characterized by a number of other cancers including colorectal, endometrial and ovarian cancer. This review covers the gynaecological aspects of managing women with HNPCC: diagnostic criteria, molecular tests for diagnosis, cancer risks and different strategies for surveillance and prevention.

RECENT FINDINGS

Studies correcting for ascertainment bias found slightly lower penetrance estimates than those obtained from high-risk families. HNPCC linked ovarian cancer presents at an earlier age and stage and has similar survival rates as sporadic cancer. In endometrial tumours, microsatellite instability or immunohistochemistry has limited effectiveness in selecting individuals for genetic testing, due to molecular differences. Population-based data indicate that a significant proportion of mismatch repair gene carriers would be missed by current clinical criteria. Effective risk prediction models complement clinical risk assessment. Effectiveness of screening is unproven and prophylactic surgery is the best preventive option for women who have completed their families. Multimodal screening protocols from the age of 30-35 years are being evaluated.

SUMMARY

Risk of endometrial cancer in women with Lynch syndrome is as high as the risk of colorectal cancer. Further research is needed to identify the appropriate strategy for clinical risk assessment and optimize screening. A multidisciplinary approach is necessary to manage these women.

Development and validation of a colon cancer risk assessment tool for patients undergoing colonoscopy

OBJECTIVES

Diagnostic criteria for hereditary colorectal cancer (CRC) are complex. "Open-access" colonoscopy makes it challenging to identify who needs genetic evaluation, intensive surveillance, and screening for extracolonic tumors. Our aim was to develop a simple, preprocedural risk assessment tool to identify who may be at highest risk for CRC.

METHODS

A total of 631 outpatients undergoing colonoscopy at two academic practices completed a questionnaire assessing personal and family histories of CRC, polyps, and Lynch syndrome (LS)-associated malignancies. Subjects were considered to be high-risk if one of the nine prespecified characteristics of hereditary CRC syndromes was met. Through recursive partitioning analysis, an algorithm of fewest questions needed to capture the most high-risk individuals was developed. The results were validated in 5,335 individuals undergoing colonoscopy at five private endoscopy centers and tested in 285 carriers of mismatch repair mutations associated with LS.

RESULTS

About 17.7% and 20.0% of individuals were classified as high-risk in the development and validation cohorts, respectively. Recursive partitioning revealed three questions that were most informative for identifying high-risk patients: (i) "Do you have a first-degree relative with CRC or LS-related cancer diagnosed before age 50?" (ii) "Have you had CRC or polyps diagnosed before age 50?" (iii) "Do you have > or =3 relatives with CRC?" When asked successively, these questions identified 77% of high-risk individuals in both cohorts and 271 of 285 (95%) of mutation carriers.

CONCLUSIONS

Approximately one in five individuals undergoing colonoscopy would benefit from further risk assessment. We developed a simple, three-question CRC Risk Assessment Tool to identify the majority of patients who require additional assessment and possible genetic evaluation.