Noralane M. Lindor

Immunohistochemistry Versus Microsatellite Instability Testing in Phenotyping Colorectal Tumors

PURPOSE To compare microsatellite instability (MSI) testing with immunohistochemical (IHC) detection of hMLH1 and hMSH2 in colorectal cancer. PATIENTS AND METHODS Colorectal cancers from 1,144 patients were assessed for DNA mismatch repair deficiency by two methods: MSI testing and IHC detection of hMLH1 and hMSH2 gene products. High-frequency MSI (MSI-H) was defined as more than 30% instability of at least five markers; low-level MSI (MSI-L) was defined as 1% to 29% of loci unstable. RESULTS Of 1,144 tumors tested, 818 showed intact expression of hMLH1 and hMSH2. Of these, 680 were microsatellite stable (MSS), 27 were MSI-H, and 111 were MSI-L. In all, 228 tumors showed absence of hMLH1 expression and 98 showed absence of hMSH2 expression: all were MSI-H. CONCLUSION IHC in colorectal tumors for protein products hMLH1 and hMSH2 provides a rapid, cost-effective, sensitive (92.3%), and extremely specific (100%) method for screening for DNA mismatch repair defects. The predictive value of normal IHC for an MSS/MSI-L phenotype was 96.7%, and the predictive value of abnormal IHC was 100% for an MSI-H phenotype. Testing strategies must take into account acceptability of missing some cases of MSI-H tumors if only IHC is performed.

Mutations in RECQL4 cause a subset of cases of Rothmund-Thomson syndrome

Rothmund-Thomson syndrome (RTS; also known as poikiloderma congenitale) is a rare, autosomal recessive genetic disorder characterized by abnormalities in skin and skeleton, juvenile cataracts, premature ageing and a predisposition to neoplasia. Cytogenetic studies indicate that cells from affected patients show genomic instability often associated with chromosomal rearrangements causing an acquired somatic mosaicism. The gene(s) responsible for RTS remains unknown. The genes responsible for Werner and Bloom syndromes (WRN and BLM, respectively) have been identified as homologues of Escherichia coli RecQ, which encodes a DNA helicase that unwinds double-stranded DNA into single-stranded DNAs. Other eukaryotic homologues thus far identified are human RECQL (Refs 13, 14), Saccharomyces cerevisiae SGS1 (Refs 15,16) and Schizosaccharomyces pombe rqh1+ (ref. 17). We recently cloned two new human helicase genes, RECQL4 at 8q24.3 and RECQL5 at 17q25, which encode members of the RecQ helicase family. Here, we report that three RTS patients carried two types of compound heterozygous mutations in RECQL4. The fact that the mutated alleles were inherited from the parents in one affected family and were not found in ethnically matched controls suggests that mutation of RECQL4 at human chromosome 8q24.3 is responsible for at least some cases of RTS.

American Society of Clinical Oncology Policy Statement Update: Genetic and Genomic Testing for Cancer Susceptibility

The American Society of Clinical Oncology (ASCO) has long affirmed that the recognition and management of individuals with an inherited susceptibility to cancer are core elements of oncology care. ASCO released its first statement on genetic testing in 1996 and updated that statement in 2003 and 2010 in response to developments in the field. In 2014, the Cancer Prevention and Ethics Committees of ASCO commissioned another update to reflect the impact of advances in this area on oncology practice. In particular, there was an interest in addressing the opportunities and challenges arising from the application of massively parallel sequencing-also known as next-generation sequencing-to cancer susceptibility testing. This technology introduces a new level of complexity into the practice of cancer risk assessment and management, requiring renewed effort on the part of ASCO to ensure that those providing care to patients with cancer receive the necessary education to use this new technology in the most effective, beneficial manner. The purpose of this statement is to explore the challenges of new and emerging technologies in cancer genetics and provide recommendations to ensure their optimal deployment in oncology practice. Specifically, the statement makes recommendations in the following areas: germline implications of somatic mutation profiling, multigene panel testing for cancer susceptibility, quality assurance in genetic testing, education of oncology professionals, and access to cancer genetic services.

The Clinical Phenotype of Lynch Syndrome Due to Germ-Line PMS2 Mutations

BACKGROUND & AIMS Although the clinical phenotype of Lynch syndrome (also known as hereditary nonpolyposis colorectal cancer) has been well described, little is known about disease in PMS2 mutation carriers. Now that mutation detection methods can discern mutations in PMS2 from mutations in its pseudogenes, more mutation carriers have been identified. Information about the clinical significance of PMS2 mutations is crucial for appropriate counseling. Here, we report the clinical characteristics of a large series of PMS2 mutation carriers. METHODS We performed PMS2 mutation analysis using long-range polymerase chain reaction and multiplex ligation-dependent probe amplification for 99 probands diagnosed with Lynch syndrome-associated tumors showing isolated loss of PMS2 by immunohistochemistry. Penetrance was calculated using a modified segregation analysis adjusting for ascertainment. RESULTS Germ-line PMS2 mutations were detected in 62% of probands (n = 55 monoallelic; 6 biallelic). Among families with monoallelic PMS2 mutations, 65.5% met revised Bethesda guidelines. Compared with the general population, in mutation carriers, the incidence of colorectal cancer was 5.2-fold higher, and the incidence of endometrial cancer was 7.5-fold higher. In North America, this translates to a cumulative cancer risk to age 70 years of 15%-20% for colorectal cancer, 15% for endometrial cancer, and 25%-32% for any Lynch syndrome-associated cancer. No elevated risk for non-Lynch syndrome-associated cancers was observed. CONCLUSIONS PMS2 mutations contribute significantly to Lynch syndrome, but the penetrance for monoallelic mutation carriers appears to be lower than that for the other mismatch repair genes. Modified counseling and cancer surveillance guidelines for PMS2 mutation carriers are proposed.

Colon Cancer Family Registry: An International Resource for Studies of the Genetic Epidemiology of Colon Cancer

Background: Family studies have served as a cornerstone of genetic research on colorectal cancer. Materials and Methods: The Colorectal Cancer Family Registry (Colon CFR) is an international consortium of six centers in North America and Australia formed as a resource to support studies on the etiology, prevention, and clinical management of colorectal cancer. Differences in design and sampling schemes ensures a resource that covers the continuum of disease risk. Two separate recruitment strategies identified colorectal cancer cases: population-based (incident case probands identified by cancer registries; all six centers) and clinic-based (families with multiple cases of colorectal cancer presenting at cancer family clinics; three centers). At this time, the Colon CFR is in year 10 with the second phase of enrollment nearly complete. In phase I recruitment (1998-2002), population-based sampling ranged from all incident cases of colorectal cancer to a subsample based on age at diagnosis and/or family cancer history. During phase II (2002-2007), population-based recruitment targeted cases diagnosed before the age of 50 years are more likely attributable to genetic factors. Standardized protocols were used to collect information regarding family cancer history and colorectal cancer risk factors, and biospecimens were obtained to assess microsatellite instability (MSI) status, expression of mismatch repair proteins, and other molecular and genetic processes. Results: Of the 8,369 case probands enrolled to date, 2,602 reported having one or more colorectal cancer–affected relatives and 799 met the Amsterdam I criteria for Lynch syndrome. A large number of affected (1,324) and unaffected (19,816) relatives were enrolled, as were population-based (4,108) and spouse (983) controls. To date, 91% of case probands provided blood (or, for a few, buccal cell) samples and 75% provided tumor tissue. For a selected sample of high-risk subjects, lymphocytes have been immortalized. Nearly 600 case probands had more than two affected colorectal cancer relatives, and 800 meeting the Amsterdam I criteria and 128, the Amsterdam II criteria. MSI testing for 10 markers was attempted on all obtained tumors. Of the 4,011 tumors collected in phase I that were successfully tested, 16% were MSI-high, 12% were MSI-low, and 72% were microsatellite stable. Tumor tissues from clinic-based cases were twice as likely as population-based cases to be MSI-high (34% versus 17%). Seventeen percent of phase I proband tumors and 24% of phase II proband tumors had some loss of mismatch repair protein, with the prevalence depending on sampling. Active follow-up to update personal and family histories, new neoplasms, and deaths in probands and relatives is nearly complete. Conclusions: The Colon CFR supports an evolving research program that is broad and interdisciplinary. The greater scientific community has access to this large and well-characterized resource for studies of colorectal cancer. (Cancer Epidemiol Biomarkers Prev 2007;16(11):2331–43)

E-cadherin germline mutations define an inherited cancer syndrome dominated by diffuse gastric cancer

To extend earlier observations of germline E‐cadherin mutations in kindreds with an inherited susceptibility to diffuse gastric cancer, we searched for germline E‐cadherin mutations in five further families affected predominantly by diffuse gastric cancer and one family with a history of diffuse gastric cancer and early‐onset breast cancer. Heterozygous inactivating mutations were found in the E‐cadherin gene in each of these families. No mutation hotspots were identified. These results demonstrate that germline mutation of the E‐cadherin gene is a common cause of hereditary diffuse gastric cancer and suggest a role for these mutations in the incidence of breast cancer. Hum Mutat 14:249–255, 1999.

A New Autosomal Dominant Disorder of Pyogenic Sterile Arthritis, Pyoderma Gangrenosum, and Acne: PAPA Syndrome

OBJECTIVE To describe a multigenerational family with transmission of an autosomal dominant disorder characterized by pyogenic arthritis, pyoderma gangrenosum, and severe cystic acne. MATERIAL AND METHODS We present a detailed case report of a 39-year-old man with arthritic changes in several joints, pyoderma gangrenosum, and cystic acne. Several relatives from three generations of his family underwent clinical and genetic investigations. The findings in this kindred are reported. RESULTS Ten affected family members in three generations manifested variable expression of a pauciarticular, nonaxial, destructive, corticosteroid-responsive arthritis that began in childhood; pyoderma gangrenosum; and severe cystic acne in adolescence and beyond. Other less commonly associated features included adult-onset insulin-dependent diabetes mellitus, proteinuria, abscess formation at the site of parenteral injections, and cytopenias attributable to sulfonamide medications. Laboratory evaluation was nondiagnostic. Genetic studies excluded linkage to the major histocompatibility locus. CONCLUSION The acronym of PAPA syndrome (pyogenic sterile arthritis, pyoderma gangrenosum, and acne) is suggested for this newly recognized pleiotropic autosomal dominant disorder. The nature of the genetic alteration in PAPA syndrome is unknown.

Risks of Lynch Syndrome Cancers for MSH6 Mutation Carriers

BACKGROUND Germline mutations in MSH6 account for 10%-20% of Lynch syndrome colorectal cancers caused by hereditary DNA mismatch repair gene mutations. Because there have been only a few studies of mutation carriers, their cancer risks are uncertain. METHODS We identified 113 families of MSH6 mutation carriers from five countries that we ascertained through family cancer clinics and population-based cancer registries. Mutation status, sex, age, and histories of cancer, polypectomy, and hysterectomy were sought from 3104 of their relatives. Age-specific cumulative risks for carriers and hazard ratios (HRs) for cancer risks of carriers, compared with those of the general population of the same country, were estimated by use of a modified segregation analysis with appropriate conditioning depending on ascertainment. RESULTS For MSH6 mutation carriers, the estimated cumulative risks to ages 70 and 80 years, respectively, were as follows: for colorectal cancer, 22% (95% confidence interval [CI] = 14% to 32%) and 44% (95% CI = 28% to 62%) for men and 10% (95% CI = 5% to 17%) and 20% (95% CI = 11% to 35%) for women; for endometrial cancer, 26% (95% CI = 18% to 36%) and 44% (95% CI = 30% to 58%); and for any cancer associated with Lynch syndrome, 24% (95% CI = 16% to 37%) and 47% (95% CI = 32% to 66%) for men and 40% (95% CI = 32% to 52%) and 65% (95% CI = 53% to 78%) for women. Compared with incidence for the general population, MSH6 mutation carriers had an eightfold increased incidence of colorectal cancer (HR = 7.6, 95% CI = 5.4 to 10.8), which was independent of sex and age. Women who were MSH6 mutation carriers had a 26-fold increased incidence of endometrial cancer (HR = 25.5, 95% CI = 16.8 to 38.7) and a sixfold increased incidence of other cancers associated with Lynch syndrome (HR = 6.0, 95% CI = 3.4 to 10.7). CONCLUSION We have obtained precise and accurate estimates of both absolute and relative cancer risks for MSH6 mutation carriers.

Concise Handbook of Familial Cancer Susceptibility Syndromes - Second Edition

1. Ataxia Telangiectasia (includes Ataxia Telangiectasia 12 Complementation Groups A, C, D, E, Louis–Barr Syndrome) 2. Basal Cell Nevus Syndrome, Nevoid Basal Cell 18 Carcinoma Syndrome, or Gorlin Syndrome 3. Beckwith–Wiedemann Syndrome 19 (Exomphalos–Macroglossia–Gigantism Syndrome) 4. Birt–Hogg–Dubé Syndrome 20 5. Bloom Syndrome 21 6. Breast/Ovarian Cancer, Hereditary (BRCA1) 22 7. Breast/Ovarian Cancer, Hereditary (BRCA2) 27 8. Carney Complex, Types I and II (formerly known as 30 NAME Syndrome [Nevi, Atrial Myxoma, Myxoid Neurofi bromata, and Ephelides] and LAMB Syndrome [Lentigines, Atrial Myxomata, Mucocutaneous Myxoma, Blue Nevi]) 9. Chordoma, Familial 31 10. Colon Cancer, Hereditary Nonpolyposis–Lynch 32 Syndrome (includes Lynch Syndrome, Hereditary Mismatch Repair Defi ciency Syndrome, Muir–Torre Syndrome, and a subset of Turcot Syndrome) 11. Costello Syndrome; Facio–Cutaneous–Skeletal Syndrome 35 12. Cowden Syndrome (Multiple Hamartoma Syndrome; 36 PTEN Hamartoma Tumor Syndrome) 13. Dyskeratosis Congenita 38 14. Esophageal Cancer, Tylosis with; Keratosis Palmaris 39 et Plantaris with Esophageal Cancer; Howel–Evans Syndrome 15. Exostosis, Hereditary Multiple (includes Type 1, 40 Type 2, Type 3, and Multiple Osteochondromas (Enchondromatosis) 16. Fanconi Anemia 41 17. Gastric Cancer, Hereditary Diffuse 43 18. Gastrointestinal Stromal Tumor; also Multiple 45 Gastrointestinal Autonomic Nerve Tumors 19. Hyperparathyroidism, Familial (includes Familial Isolated 46 Hyperparathyroidism and Familial Hyperparathyroidism with Multiple Ossifying Jaw Fibromas (aka Hereditary Hyperparathyroidism-Jaw Tumor Syndrome); Familial Cystic Parathyroid Adenomatosis) 20. Leukemia, Acute Myeloid, Familial 47 21. Leukemia, Chronic Lymphocytic, Familial 47 22. Li–Fraumeni Syndrome, including Li-Fraumeni-Like 48 Syndrome 23. Lymphoma, Hodgkin, Familial 50 24. Lymphoma, Non-Hodgkin, Familial 51 25. Melanoma, Hereditary Multiple (includes Dysplastic 52 Nevus Syndrome, Familial Atypical Mole–Malignant Melanoma Syndrome, Melanoma–Pancreatic Carcinoma Syndrome, Melanoma–Astrocytoma Syndrome, Familial Uveal Melanoma) 26. Mosaic Variegated Aneuploidy 56 27. Multiple Endocrine Neoplasia Type 1 (MEN1; Wermer 57 Syndrome; includes Zollinger–Ellison [Z–E] Syndrome; also Multiple Endocrine Neoplasia Type 1B [MEN 1B] noted) 28. Multiple Endocrine Neoplasia Type 2A, 2B 58 (Sipple Syndrome), and Familial Medullary Thyroid Cancer 29. Multiple Myeloma, Familial 60 30. Neuroblastoma, Hereditary 61 31. Neurofi bromatosis Type 1 (NF1; includes von 61 Recklinghausen Disease) 32. Neurofi bromatosis Type 2 (sometimes called 63 Central Neurofi bromatosis or Bilateral Acoustic Neurofi bromatosis) 33. Nijmegen Breakage Syndrome (formerly called 65 Ataxia Telangiectasia Variant or AT-V1; includes Berlin Breakage Syndrome, formerly called AT-V2) 34. Pancreatic Cancer, Hereditary 66 35. Paraganglioma, Hereditary 67 36. Peutz–Jeghers Syndrome 69 37. Polyposis, Familial Adenomatous (includes 71 Gardner Syndrome, Familial Multicentric Fibromatosis and/or Hereditary Desmoid Disease, and a subset of Turcot Syndrome) 38. Polyposis, Familial Juvenile (includes Hereditary 73 Mixed Polyposis Types 1 and 2) 39. Polyposis, MYH-Associated (MAP) 74 40. Prostate Cancer, Hereditary 75

Identification of Lynch syndrome among patients with colorectal cancer.

CONTEXT Lynch syndrome is the most common form of hereditary colorectal cancer (CRC) and is caused by germline mutations in DNA mismatch repair (MMR) genes. Identification of gene carriers currently relies on germline analysis in patients with MMR-deficient tumors, but criteria to select individuals in whom tumor MMR testing should be performed are unclear. OBJECTIVE To establish a highly sensitive and efficient strategy for the identification of MMR gene mutation carriers among CRC probands. DESIGN, SETTING, AND PATIENTS Pooled-data analysis of 4 large cohorts of newly diagnosed CRC probands recruited between 1994 and 2010 (n = 10,206) from the Colon Cancer Family Registry, the EPICOLON project, the Ohio State University, and the University of Helsinki examining personal, tumor-related, and family characteristics, as well as microsatellite instability, tumor MMR immunostaining, and germline MMR mutational status data. MAIN OUTCOME Performance characteristics of selected strategies (Bethesda guidelines, Jerusalem recommendations, and those derived from a bivariate/multivariate analysis of variables associated with Lynch syndrome) were compared with tumor MMR testing of all CRC patients (universal screening). RESULTS Of 10,206 informative, unrelated CRC probands, 312 (3.1%) were MMR gene mutation carriers. In the population-based cohorts (n = 3671 probands), the universal screening approach (sensitivity, 100%; 95% CI, 99.3%-100%; specificity, 93.0%; 95% CI, 92.0%-93.7%; diagnostic yield, 2.2%; 95% CI, 1.7%-2.7%) was superior to the use of Bethesda guidelines (sensitivity, 87.8%; 95% CI, 78.9%-93.2%; specificity, 97.5%; 95% CI, 96.9%-98.0%; diagnostic yield, 2.0%; 95% CI, 1.5%-2.4%; P < .001), Jerusalem recommendations (sensitivity, 85.4%; 95% CI, 77.1%-93.6%; specificity, 96.7%; 95% CI, 96.0%-97.2%; diagnostic yield, 1.9%; 95% CI, 1.4%-2.3%; P < .001), and a selective strategy based on tumor MMR testing of cases with CRC diagnosed at age 70 years or younger and in older patients fulfilling the Bethesda guidelines (sensitivity, 95.1%; 95% CI, 89.8%-99.0%; specificity, 95.5%; 95% CI, 94.7%-96.1%; diagnostic yield, 2.1%; 95% CI, 1.6%-2.6%; P < .001). This selective strategy missed 4.9% of Lynch syndrome cases but resulted in 34.8% fewer cases requiring tumor MMR testing and 28.6% fewer cases undergoing germline mutational analysis than the universal approach. CONCLUSION Universal tumor MMR testing among CRC probands had a greater sensitivity for the identification of Lynch syndrome compared with multiple alternative strategies, although the increase in the diagnostic yield was modest.