Lisa Happerfield

MLH1 Promoter Methylation, Diet, and Lifestyle Factors in Mismatch Repair Deficient Colorectal Cancer Patients From EPIC-Norfolk

There is conflicting evidence for the role diet and lifestyle play in the development of mismatch repair (MMR)-deficient colorectal cancers (CRC). In this study, associations between MMR deficiency, clinicopathological characteristics, and dietary and lifestyle factors in sporadic CRC were investigated. Tumor samples from 185 individuals in the EPIC-Norfolk study were analyzed for MLH1 gene promoter methylation and microsatellite instability (MSI). Dietary and lifestyle data were collected prospectively using 7-day food diaries (7dd) and questionnaires. MMR-deficient tumor cases (MLH1 promoter methylation positive, MSI-H) were more likely to be female, older at diagnosis, early Dukes’ stage (A/B), and proximal in location (MSI-H P = 0.03, 0.03, 0.02, and 0.001, respectively). Tumors with positive MLH1 promoter methylation (>20%) were associated with poor differentiation (P = 0.03). Low physical activity was associated with cases without MSI (P = 0.05). MMR deficiency was not significantly associated with cigarette smoking or alcohol, folate, fruit, vegetable, or meat consumption. We conclude that MMR-deficient tumors represent a distinct subset of sporadic CRC that are proximal in location, early Dukes’ stage, and poorly differentiated, in cases that are female and older at diagnosis. There is no overall role for diet and lifestyle in MMR status in CRC, consistent with age-related susceptibility to MLH1 promoter methylation.

Megaoesophagus in Rassf1a-null mice

Megaoesophagus, or oesophageal achalasia, is a neuromuscular disorder characterized by an absence of peristalsis and flaccid dilatation of the oesophagus, resulting in the retention of ingesta in the dilated segment. The aetiology and pathogenesis of idiopathic (or primary) megaoesophagus are still poorly understood and very little is known about the genetic causes of megaoesophagus in humans. Attempts to develop animal models of this condition have been largely unsuccessful and although the ICRC/HiCri strain of mice spontaneously develop megaoesophagus, the underlying genetic cause remains unknown. In this report, we show that aged Rassf1a‐null mice have an enhanced susceptibility to megaoesophagus compared with wild‐type littermates (∼20%vs. ∼2% incidence respectively; P = 0.01). Histological examination of the dilated oesophaguses shows a reduction in the numbers of nerve cells (both ganglia and nerve fibres) in the myenteric plexus of the dilated mid and lower oesophagus that was confirmed by S100 immunohistochemistry. There was also a chronic inflammatory infiltrate and subsequent fibrosis of the myenteric plexus and the muscle layers. These appearances closely mimic the gross and histopathological findings in human cases of megaoesophagus/achalasia, thus demonstrating that this is a representative mouse model of the disease. Thus, we have identified a genetic cause of the development of megaoesophagus/achalasia that could be screened for in patients, and may eventually facilitate the development of therapies that could prevent further progression of the disease once it is diagnosed at an early stage.

Familial adrenocortical carcinoma in association with Lynch syndrome

Context: Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with a poor prognosis. Although the majority of childhood ACC arises in the context of inherited cancer susceptibility syndromes, it remains less clear whether a hereditary tumor predisposition exists for the development of ACC in adults. Here, we report the first occurrence of familial ACC in a kindred with Lynch syndrome resulting from a pathogenic germline MSH2 mutation. Case: A 54-year-old female with a history of ovarian and colorectal malignancy was found to have an ACC. A detailed family history revealed her mother had died of ACC and her sister had previously been diagnosed with endometrial and colorectal cancers. A unifying diagnosis of Lynch syndrome was considered, and immunohistochemical analyses demonstrated loss of MSH2 and MSH6 expression in both AACs (proband and her mother) and in the endometrial carcinoma of her sister. Subsequent genetic screening confirmed the presence of a germline MSH2 mutation (resulting in deletions of exons 1–3) in the proband and her sister. Conclusion: Our findings provide strong support for the recent proposal that ACC should be considered a Lynch syndrome-associated tumor and included in the Amsterdam II clinical diagnostic criteria. We also suggest that screening for ACC should be considered in cancer surveillance strategies directed at individuals with germline mutations in DNA mismatch repair genes.

Multilocus Inherited Neoplasia Alleles Syndrome: A Case Series and Review

Mendelian causes of inherited cancer susceptibility are mostly rare and characterized by variable expression and incomplete penetrance. Phenotypic variability may result from a range of causes including locus heterogeneity, allelic heterogeneity, genetic and environmental modifier effects, or chance. Another potential cause is the presence of 2 or more inherited cancer predisposition alleles in the same individual. Although the frequency of such occurrences might be predicted to be low, such cases have probably been underascertained because standard clinical practice has been to test candidate inherited cancer genes sequentially until a pathogenic mutation is detected. However, recent advances in next-generation sequencing technologies now provide the opportunity to perform simultaneous parallel testing of large numbers of inherited cancer genes. Herein we provide examples of patients who harbor pathogenic mutations in multiple inherited cancer genes and review previously published examples to illustrate the complex genotype-phenotype relationships in these cases. We suggest that clinicians should proactively consider the likelihood of this phenomenon (referred to herein as multilocus inherited neoplasia alleles syndrome [MINAS]) in patients with unusual inherited cancer syndrome phenotypes. To facilitate the clinical management of novel cases of MINAS, we have established a database to collect information on what is likely to be an increasingly recognized cohort of such individuals.

Application of Molecular Diagnostics to Hereditary Nonpolyposis Colorectal Cancer

Hereditary nonpolyposis colorectal cancer is a tumor predis– position syndrome characterised by a propensity to develop, typically, but by no means exclusively, young‐onset colorectal and other cancers (1). The condition was first described in 1913 by the US pathologist Warthin in a comprehensive survey of familial cancer (2). He was stimulated to make this study because his seamstress was depressed at the thought of dying prematurely from bowel or womb cancer, as had many of her relatives. She was a member of Family “ G” in his original arti–cle, which incidentally contains examples of most of the cancer genetic conditions recognized today (2). Family “G” was redis– covered in the 1960s by Lynch, although it was not at first real-ized that it was one of Warthins original families (3,4). Lynch later made a distinction between families with only bowel can– cer (Lynch syndrome type 1: site‐specific colorectal cancer) and families with several types of cancer, including bowel (Lynch syndrome type 2: family cancer syndrome). Given the propensity to bowel cancer, but without the polyposis charac– teristic of familial adenomatous polyposis (FAP), the all embracing term “hereditary nonpolyposis colorectal cancer” (HNPCC) is now used (1). However, having to explain all this in the clinic makes the idea of going back to calling it Lynch or family cancer syndrome rather attractive.

Translating In Vivo Metabolomic Analysis of Succinate Dehydrogenase–Deficient Tumors Into Clinical Utility

Purpose Mutations in the mitochondrial enzyme succinate dehydrogenase (SDH) subunit genes are associated with a wide spectrum of tumours including phaeochromocytoma and paraganglioma (PPGL) 1, 2, gastrointestinal stromal tumours (GIST) 3, renal cell carcinoma (RCC) 4 and pituitary adenomas5. SDH-related tumorigenesis is believed to be secondary to accumulation of the oncometabolite succinate. Our aim was to investigate the potential clinical applications of MRI spectroscopy (1H-MRS) in a range of suspected SDH-related tumours. Patients and methods Fifteen patients were recruited to this study. Respiratory-gated single-voxel 1H-MRS was performed at 3T to quantify the content of succinate at 2.4 ppm and choline at 3.22 ppm. Results A succinate peak was seen in six patients, all of whom had a germline SDHx mutation or loss of SDHB by immunohistochemistry. A succinate peak was also detected in two patients with a metastatic wild-type GIST (wtGIST) and no detectable germline SDHx mutation but a somatic epimutation in SDHC. Three patients without a tumour succinate peak retained SDHB expression, consistent with SDH functionality. In six cases with a borderline or absent peak, technical difficulties such as motion artefact rendered 1H-MRS difficult to interpret. Sequential imaging in a patient with a metastatic abdominal paraganglioma demonstrated loss of the succinate peak after four cycles of [177Lu]-DOTATATE, with a corresponding biochemical response in normetanephrine. Conclusions This study has demonstrated the translation into clinical practice of in vivo metabolomic analysis using 1H-MRS in patients with SDH-deficient tumours. Potential applications include non-invasive diagnosis and disease stratification, as well as monitoring of tumour response to targeted treatments.

Multilocus inherited neoplasia alleles syndrome

Mendelian causes of inherited cancer susceptibility are mostly rare and characterized by variable expression and incomplete penetrance. Phenotypic variability may result from a range of causes including locus heterogeneity, allelic heterogeneity, genetic and environmental modifier effects, or chance. Another potential cause is the presence of 2 or more inherited cancer predisposition alleles in the same individual. Although the frequency of such occurrences might be predicted to be low, such cases have probably been underascertained because standard clinical practice has been to test candidate inherited cancer genes sequentially until a pathogenic mutation is detected. However, recent advances in next-generation sequencing technologies now provide the opportunity to perform simultaneous parallel testing of large numbers of inherited cancer genes. Herein we provide examples of patients who harbor pathogenic mutations in multiple inherited cancer genes and review previously published examples to illustrate the complex genotype-phenotype relationships in these cases. We suggest that clinicians should proactively consider the likelihood of this phenomenon (referred to herein as multilocus inherited neoplasia alleles syndrome [MINAS]) in patients with unusual inherited cancer syndrome phenotypes. To facilitate the clinical management of novel cases of MINAS, we have established a database to collect information on what is likely to be an increasingly recognized cohort of such individuals.

Multilocus Inherited Neoplasia Alleles Syndrome (MINAS): Case Series and Literature Review

Mendelian causes of inherited cancer susceptibility are mostly rare and characterized by variable expression and incomplete penetrance. Phenotypic variability may result from a range of causes including locus heterogeneity, allelic heterogeneity, genetic and environmental modifier effects, or chance. Another potential cause is the presence of 2 or more inherited cancer predisposition alleles in the same individual. Although the frequency of such occurrences might be predicted to be low, such cases have probably been underascertained because standard clinical practice has been to test candidate inherited cancer genes sequentially until a pathogenic mutation is detected. However, recent advances in next-generation sequencing technologies now provide the opportunity to perform simultaneous parallel testing of large numbers of inherited cancer genes. Herein we provide examples of patients who harbor pathogenic mutations in multiple inherited cancer genes and review previously published examples to illustrate the complex genotype-phenotype relationships in these cases. We suggest that clinicians should proactively consider the likelihood of this phenomenon (referred to herein as multilocus inherited neoplasia alleles syndrome [MINAS]) in patients with unusual inherited cancer syndrome phenotypes. To facilitate the clinical management of novel cases of MINAS, we have established a database to collect information on what is likely to be an increasingly recognized cohort of such individuals.

802 SOMATIC MUTATIONS OF KCNJ5 ARE COMMON IN ALDOSTERONE-PRODUCING ADENOMAS OF THE ADRENAL, AND DISTINGUISH A PHENOTYPE OF YOUNGER WOMEN WITH ZF-LIKE LARGE ADENOMAS FROM OLDER MEN WITH ZG-LIKE SMALL ADENOMAS

Background: Among aldosterone-producing adenomas (APAs), heterogeneity of phenotype is well recognized. Chois finding of KCNJ5 mutations in 8/22 APAs [1], offered a possible explanation for heterogeneity and hence prompted the question whether there are genotype:phenotype correlations. Method: The K+-selectivity region of KCNJ5 was sequenced in 46 APAs. Each was blindly histologically graded. A microarray comparison of ZF- vs ZG-like APAs suggested putative ZG genes, whose expression was compared between ZG and ZF cells from normal adrenal using laser capture microdissection (LCM). Confirmed ZG genes were compared between mutant and wild-type APA. Immunohistochemistry for KCNJ5 was undertaken in adrenals with and without the mutation. Result: 20/46 APAs (43%(95%CI[29,58]%)) had KCNJ5 somatic mutations. Mutant APAs were larger, 2.27 vs 0.78cm3, (p = 0.001). Regression analysis distinguished: [i] younger women, with mainly mutant, larger APAs, from [ii] older men with mainly wild-type smaller APAs (Figure). APAs with KCNJ5 mutation had histological appearance of ZF cells, in particular the classical feature of higher cytoplasm to nucleus ratio. Genes confirmed as ZG-selective on LCM were less abundant in mutant APAs while the ZF-gene CYP17A1 was higher (0.51 vs 0.15, P = 0.011). KCNJ5 staining was observed in all APAs regardless of genotype. Figure. No caption available. Conclusion: The mutant and wild-type phenotypes differ by age, gender, size, gene expression profile and histology, and may arise respectively from ZF and ZG. Small ZG-like APAs may elude diagnosis at a young age and progress to cause resistant hypertension. ReferenceChoi M et al. K+-channel mutations in adrenal aldosterone-producing adenomas and hereditary hypertension. Science 2011;331:768-772.