Case Report Series: Aggressive HR Deficient Colorectal Cancers Related to BRCA1 Pathogenic Germline Variants

Objective

The link between BRCA1 and homologous recombination deficiency (HRD) in cancer has gained importance with the emergence of new targeted cancer treatments, while the available data on the role of the gene in colorectal cancer (CRC) remain contradictory. The aim of this case series was to elucidate the role of known pathogenic BRCA1 variants in the development of early-onset CRC.

Design

Patients were evaluated using targeted next generation sequencing, exome sequencing and chromosomal microarray analysis of the paired germline and tumor samples. These results were used to calculate the HRD score and the frequency of mutational signatures in the tumors.

Results

Three patients with metastatic CRC were heterozygous for a previously known BRCA1 nonsense variant. All tumors showed remarkably high HRD scores, and the HRD-related signature 3 had the second highest contribution to the somatic pattern of variant accumulation in the samples (23% in 1 and 2, and 13% in sample 3).

Conclusions

A BRCA1 germline pathogenic variant can be involved in CRC development through HRD. Thus, BRCA1 testing should be considered in young patients with a personal history of microsatellite stable CRC as this could further allow a personalized treatment approach.

[Heredity and cancer]

A personal or family history of cancer has now become the primary cause of genetic consultations. In recent years, various genes have been identified that are associated with a more or less marked genetic predisposition to the development of cancers. The syndrome associated with the hereditary risk of breast and ovarian cancer and the Lynch syndrome are the most frequent ones, but there are many other, much less common, situations associated with familial cancer risk. In most cases, there are clear recommendations regarding the indications for genetic testing and the follow-up of patients identified as having a predisposition to cancer. At the CHU of Liège, we currently perform more than 1.400 oncogenetic consultations per year and we maintain a positivity rate of genetic tests performed in this indication higher than 10%. In this way, we allow a multidisciplinary care of patients with a high oncological risk and participate in a prevention and surveillance activity. We also pay increasing attention to the hereditary risk associated with pediatric cancers and to patients with multiple cancers, especially when these develop at an early age. Finally, the oncogenetic consultation must consider the psychological, ethical and legal aspects of a diagnosis that involves the patient and his or her future, but also the whole family.

Screening of germline mutations in young Rwandan patients with breast cancers

Background

In Sub‐Saharan Africa breast cancer is commonly detected at younger age and the profile is more aggressive with a high mortality rate compared to the European countries. It is suggested that African‐specific genetic background plays a key role in this matter. The present study aimed at understanding the role of genetic factors in breast cancer development in young Rwandan.

Methods

We performed a massive parallel sequencing on Illumina MiSeq NGS system for the screening of 26 genes associated with hereditary breast cancer from 40 patients under 35 years old from two University Teaching Hospitals in Kigali, Rwanda. Sanger sequencing was used to confirm pathogenic and likely pathogenic mutations.

Results

Five patients out of 40 (12.5%) presented with pathogenic mutations including four patients (10%) carrying BRCA1 or BRCA2 pathogenic variants. One patient showed a missense likely pathogenic TP53 variant. We have also detected additional missense, intronic, and 3’UTR variants of unknown significance in all study participants.

Conclusion

This preliminary study suggests that the frequency of germline mutations in young Rwandan patients with breast cancer is similar to the observations made in Caucasians. However, further large studies including patients and controls are needed to better understand the impact of genetic factors as well as the environmental risk factors in the development of breast cancer in young Rwandans.

Screening of germline mutations in Rwandan young patients with breast cancer. The next generation sequencing detected pathogenic BRCA 1 and 2 mutations in 6 patients. We have also detected additional missense, intronic, and 3’UTR variants of unknown significance in all study participants.

[Hereditary diffuse gastric cancer : case serie of 8 patients from a single family and literature review]

Hereditary diffuse gastric cancer is a form of gastric cancer associated, in about 40 % of cases, with a germline mutation of the CDH1 gene. The management of patients with a pathogenic mutation of this gene is based on total prophylactic gastrectomy because, until proven otherwise, endoscopic monitoring is insufficient. We report a series of eight patients with pathogenic CDH1 mutation who underwent total prophylactic gastrectomy in our centre.

Genetic assessment and folate receptor autoantibodies in infantile-onset cerebral folate deficiency (CFD) syndrome

INTRODUCTION

Cerebral folate deficiency (CFD) syndromes are defined as neuro-psychiatric conditions with low CSF folate and attributed to different causes such as autoantibodies against the folate receptor-alpha (FR) protein that can block folate transport across the choroid plexus, FOLR1 gene mutations or mitochondrial disorders. High-dose folinic acid treatment restores many neurologic deficits.

STUDY AIMS AND METHODS

Among 36 patients from 33 families the infantile-onset CFD syndrome was diagnosed based on typical clinical features and low CSF folate. All parents were healthy. Three families had 2 affected siblings, while parents from 4 families were first cousins. We analysed serum FR autoantibodies and the FOLR1 and FOLR2 genes. Among three consanguineous families homozygosity mapping attempted to identify a monogenetic cause. Whole exome sequencing (WES) was performed in the fourth consanguineous family, where two siblings also suffered from polyneuropathy as an atypical finding.

RESULTS

Boys (72%) outnumbered girls (28%). Most patients (89%) had serum FR autoantibodies fluctuating over 5-6 weeks. Two children had a genetic FOLR1 variant without pathological significance. Homozygosity mapping failed to detect a single autosomal recessive gene. WES revealed an autosomal recessive polynucleotide kinase 3´phosphatase (PNKP) gene abnormality in the siblings with polyneuropathy.

DISCUSSION

Infantile-onset CFD was characterized by serum FR autoantibodies as its predominant pathology whereas pathogenic FOLR1 gene mutations were absent. Homozygosity mapping excluded autosomal recessive inheritance of any single responsible gene. WES in one consanguineous family identified a PNKP gene abnormality that explained the polyneuropathy and also its contribution to the infantile CFD syndrome because the PNKP gene plays a dual role in both neurodevelopment and immune-regulatory function. Further research for candidate genes predisposing to FRα-autoimmunity is suggested to include X-chromosomal and non-coding DNA regions.

In silico analysis of structural modifications in and around the integrin αIIb genu caused by ITGA2B variants in human platelets with emphasis on Glanzmann thrombasthenia

BACKGROUND

Studies on the inherited bleeding disorder, Glanzmann thrombasthenia (GT), have helped define the role of the αIIbβ3 integrin in platelet aggregation. Stable bent αIIbβ3 undergoes conformation changes on activation allowing fibrinogen binding and its taking an extended form. The αIIb genu assures the fulcrum of the bent state. Our goal was to determine how structural changes induced by missense mutations in the αIIb genu define GT phenotype.

METHODS

Sanger sequencing of ITGA2B and ITGB3 in the index case followed by in silico modeling of all known GT-causing missense mutations extending from the lower part of the β-propeller, and through the thigh and upper calf-1 domains.

RESULTS

A homozygous c.1772A>C transversion in exon 18 of ITGA2B coding for a p.Asp591Ala substitution in an interconnecting loop of the lower thigh domain of αIIb in a patient with platelets lacking αIIbβ3 led us to extend our in silico modeling to all 16 published disease-causing missense variants potentially affecting the αIIb genu. Modifications of structuring H-bonding were the major cause in the thigh domain although one mutation gave mRNA decay. In contrast, short-range changes induced in calf-1 appeared minor suggesting long-range effects. All result in severe to total loss of αIIbβ3 in platelets. The absence of mutations within a key Ca2+-binding loop in the genu led us to scan public databases; three potential single allele variants giving major structural changes were identiffied suggesting that this key region is not protected from genetic variation.

CONCLUSIONS

It appears that the αIIb genu is the object of stringent quality control to prevent platelets from circulating with activated and extended integrin.

Innovative methodology for the identification of soluble biomarkers in fresh tissues

The identification of diagnostic and prognostic biomarkers from early lesions, measurable in liquid biopsies remains a major challenge, particularly in oncology. Fresh human material of high quality is required for biomarker discovery but is often not available when it is totally required for clinical pathology investigation. Hence, all OMICs studies are done on residual and less clinically relevant biological samples. Here after, we present an innovative, simple, and non-destructive, procedure named EXPEL that uses rapid, pressure-assisted, interstitial fluid extrusion, preserving the specimen for full routine clinical pathology investigation. In the meantime, the technique allows a comprehensive OMICs analysis (proteins, metabolites, miRNAs and DNA). As proof of concept, we have applied EXPEL on freshly collected human colorectal cancer and liver metastases tissues. We demonstrate that the procedure efficiently allows the extraction, within a few minutes, of a wide variety of biomolecules holding diagnostic and prognostic potential while keeping both tissue morphology and antigenicity unaltered. Our method enables, for the first time, both clinicians and scientists to explore identical clinical material regardless of its origin and size, which has a major positive impact on translation to the clinic.

[How to avoid overmedicalization of the elderly patient ?]

Over-medicalization is a broad concept, which also concerns the elderly patient. It encompasses both over-diagnosis and over-treatment. An increasing awareness of this issue has emerged since 2013, with the first " Preventing Overdiagnosis " conference. Currently, Evidence-Based Medicine does not prevent over-diagnosis. Indeed, the presence of geriatric characteristics such as multiple comorbidities, polypharmacy and frailty can lead to misdiagnosis and to potentially deleterious treatment. Subclinical hypothyroidism and Alzheimer's disease are two examples of pitfalls in the interpretation of biological and para-clinical data that may lead to the administration of useless treatment. Different issues are discussed to identify the causes of over-medicalization and to better prevent it.

Breast cancer in a male-to-female transsexual patient with a BRCA2 mutation

Breast cancer is rare in male patients. Certain predisposing factors, be they genetic (e.g., BRCA2 gene mutations) or hormonal (imbalance between estrogen and androgen levels), have been implicated in male breast cancer pathophysiology. Male-to-female (MtF) transsexualism is a condition that generally involves cross-sex hormone therapy. Anti-androgens and estrogens are used to mimic the female hormonal environment and induce the cross-sex secondary characteristics. In certain situations, the change in the hormonal milieu can be disadvantageous and favor the development of hormone-dependent pathologies, such as cancer. We report a case of a MtF transgender patient who developed breast cancer after 7 years of cross-sex hormonal therapy. The patient was found to be BRCA2 positive, and suffered recurrent disease. The patient was unaware of being a member of an established BRCA2 mutation-positive kindred. This represents the first case of a BRCA2 mutation predisposing to breast cancer in a MtF transgender patient.

[The clinical use of the IWG diagnostic criteria for Alzheimer's disease: A retrospective study in a memory clinic]

INTRODUCTION

In recent years knowledge about Alzheimer's disease (AD) presented a major change since the availability of new diagnostic criteria incorporating biomarkers within the known cl inical criteria. Such criteria were elaborated by NIA-AA (National Institute on Aging - Alzheimer's Association) for clinical use and IWG (International Working Group) for research purpose. The aim of this study is to investigate the use of complementary examinations included in the NIA-AA and IWG criteria in a memory clinic characterized by a heterogenous population of patients.

METHODS

We retrospectively reviewed patient's characteristics of cases consulting between 01/01/2010 and 31/12/2013 based on the implementation of three additional tests: neuropsychological testing, measurement of cerebrospinal fluid (CSF) biomarkers and brain MRI. Patients were compared according to their origins.

RESULTS

919 patients' medical records were included in the study, 20 % of which were from immigrant background. Non-European Union migrants underwent less neuropsychological testing and more lumbar punctures in comparison with the local population.

CONCLUSION

CSF biomarkers allow defining an objective diagnostic component of AD by suppressing the variability due to language, culture, education and the clinical presentation of the disease. Despite the known use in the research domain but not yet validated for clinical use, the IWG criteria are applied in heterogeneous populations with a high percentage of migrants, especially when the results of the neuropsychological testing are poorly contributive. We expect recommendations for clinical use of the CSF biomarkers or better cognitive assessment methods for these populations in the future.

[PHARMACOGENOMICS AND PERSONALIZED MEDICINE: TOWARDS A SYSTEMATIC GENOMIC SCREENING?]

Recent advances in medical genomics open new perspectives for personalized medicine through the identification of genetic variants that influence drug response and/or the risk of side effects. Today, the clinical applications of pharmacogenetics remain scarce as a consequence of the cost and turn-around-time of genetic tests. However, a few tests are recommended, for instance before the prescription of some anti-cancer agents or the anti-retroviral agent abacavir. In the future, we will probably move either towards rapid targeted tests or towards a large screening, before any diagnosis, of all the genetic factors influencing the therapeutic response. In that case, physicians will have to consult the patient genomic data before drug prescription in order to personalize the choice of the therapeutic agent or its dosage. However, such a genomic approach brings economical and ethical questions and will require further progress in our capacity to interpret and store the personal genomic data without compromising their confidentiality.

BRCA1 germline mutation and glioblastoma development: report of cases

BACKGROUND

Germline mutations in breast cancer susceptibility gene 1 (BRCA1) increase the risk of breast and ovarian cancers. However, no association between BRCA1 germline mutation and glioblastoma malignancy has ever been highlighted. Here we report two cases of BRCA1 mutated patients who developed a glioblastoma multiform (GBM).

CASES PRESENTATION

Two patients diagnosed with triple negative breast cancer (TNBC) were screened for BRCA1 germline mutation. They both carried a pathogenic mutation introducing a premature STOP codon in the exon 11 of the BRCA1 gene. Few years later, both patients developed a glioblastoma and a second breast cancer. In an attempt to clarify the role played by a mutated BRCA1 allele in the GBM development, we investigated the BRCA1 mRNA and protein expression in breast and glioblastoma tumours for both patients. The promoter methylation status of this gene was also tested by methylation specific PCR as BRCA1 expression is also known to be lost by this mechanism in some sporadic breast cancers.

CONCLUSION

Our data show that BRCA1 expression is maintained in glioblastoma at the protein and the mRNA levels, suggesting that loss of heterozygosity (LOH) did not occur in these cases. The protein expression is tenfold higher in the glioblastoma of patient 1 than in her first breast carcinoma, and twice higher in patient 2. In agreement with the high protein expression level in the GBM, BRCA1 promoter methylation was not observed in these tumours. In these two cases, despite of a BRCA1 pathogenic germline mutation, the tumour-suppressor protein expression is maintained in GBM, suggesting that the BRCA1 mutation is not instrumental for the GBM development.

[Screening of the risk of functional decline performed by an inpatient geriatric consultation team in a general hospital]

The Mobile Geriatric Team (MGT) is part of the Geriatric Care Program and aims to provide interdisciplinary geriatric expertise to other professionals for old patients hospitalized outside geriatric department. Our hospital has a MGT since 2008. Our objective is to retrospectively describe the population of patients of 75 years and older hospitalized outside the geriatric ward and screened for the risk of functional decline by the MGT between 1 October 2009 and 30 September 2011. We recorded the risk of functional decline, as indicated by the Identification of Senior At Risk score (ISAR) performed within 48 h after admission, place of living, discharge destination, Mini Mental State Examination (MMSE) and Geriatric Depression Scale (GDS) scores. In two years, 1.568 patients > or = 75 Y were screened with the ISAR score (mean age 82.5 Y, 60.7% of women). We identified 833 patients with a high-risk of functional decline (ISAR > or = 3). The majority of high-risk subjects (78%) were living at home before hospitalization and 58.7% returned home after discharge. Depression and cognitive impairment were identified among respectively 41% and 59% of high-risk subjects. Only 128 patients were admitted for fall. Most of the faller patients were living at home prior hospitalization and had an ISAR score > or = 3. The MGT allowed identifying many patients > or = 75 Y living at home and presenting with high-risk of functional decline and geriatric syndromes, confirming that good screening procedures are necessary to optimize management of hospitalized olders. Most of faller patients have an ISAR score > or = 3 and should benefit a comprehensive geriatric assessment.

Learning curve in tracheal allotransplantation

The first vascularized tracheal allotransplantation was performed in 2008. Immunosuppression was stopped after forearm implantation and grafting of the recipient mucosa to the internal site of the transplant. Nine months after forearm implantation, the allograft was transplanted to the tracheal defect on the radial blood vessels. Since then, four additional patients have undergone tracheal allotransplantation, three (patients 2-4) for long-segment stenosis and one (patient 5) for a low-grade chondrosarcoma. Our goal was to reduce the time between forearm implantation and orthotopic transplantation and to determine a protocol for safe withdrawal of immunosuppressive therapy. Following forearm implantation, all transplants became fully revascularized over 2 months. Withdrawal of immunosuppression began 4 months after graft implantation and was completed within 6 weeks in cases 2-4. Repopulation of the mucosal lining by recipient cells, to compensate for the necrosis of the donor mucosa, was not complete. This resulted in partial loss of the allotransplant in patients 2-4. In patient 5, additional measures promoting recipient cell repopulation were made. The trachea may be used as a composite tissue allotransplant after heterotopic revascularization in the forearm. Measures to maximize recipient cell repopulation may be important in maintaining the viability of the transplant after cessation of immunosuppression.

3-years experience review of neonatal screening for hemoglobin disorders using tandem mass spectrometry

BACKGROUND

Neonatal screening programs for sickle cell disease are common in North America and in some European countries. Isoelectric Focusing or High Performance Liquid Chromatography is the main technique used for hemoglobin variant detection.

METHODS

Since tandem mass spectrometry is being used for screening of inherited metabolic disorders and allows protein identification, we had developed an application to identify the most relevant hemoglobin mutations with this technology.

RESULTS

This approach had been previously validated and has been routinely applied in our laboratory for the last three years. We report here our experience with this new method in the field, applied to our East-Belgian population.

CONCLUSIONS

To conclude, mass spectrometry provides an efficient alternative approach for laboratories performing neonatal screening of hemoglobin disorders.

Improved molecular diagnostics of idiopathic short stature and allied disorders: quantitative polymerase chain reaction-based copy number profiling of SHOX and pseudoautosomal region 1

CONTEXT

Short stature has an incidence of three in 100 in children. Reliable molecular genetic testing may be crucial in the context of beneficial disease management. Deletions spanning or surrounding the SHOX gene account for a significant proportion of patients with idiopathic short stature (ISS) and allied disorders, such as Leri-Weill dyschondrosteosis.

OBJECTIVE

Several shortcomings of current strategies for copy number profiling of the SHOX region prompted us to develop an improved test for molecular diagnostics of the SHOX region.

DESIGN AND RESULTS

We introduced a quantitative PCR (qPCR)-based copy number profiling test, consisting of 11 amplicons targeting clinically relevant regions, i.e. the SHOX gene and regulatory regions. To ensure an optimal sensitivity and specificity, this test was validated in 32 controls and 18 probands with previously identified copy number changes. In addition, 152 probands with SHOX-associated phenotypes were screened, revealing 10 novel copy number changes.

CONCLUSION

This highly validated qPCR test supersedes other approaches for copy number screening of the SHOX region in terms of reliability, accuracy, and cost efficiency. In addition, another strong point is the fact that it can be easily implemented in any standard equipped molecular laboratory. Our qPCR-based test is highly recommended for molecular diagnostics of idiopathic short stature and allied disorders.

Deletion of Xpter encompassing the SHOX gene and PAR1 region in familial patients with Leri-Weill Dyschondrosteosis syndrome

Heterozygote deletions or mutations of pseudoautosomal 1 region (PAR1) encompassing the short stature homeobox-containing (SHOX) gene cause Leri-Weill Dyschondrosteosis (LWD), which is a dominantly inherited osteochondroplasia characterized by short stature with mesomelic shortening of the upper and lower limbs and Madelung deformity of the wrists. SHOX is expressed by both sex chromosomes in males and females and plays an important role in bone growth and development. Clinically, the LWD expression is variable and more severe in females than males due to sex differences in oestrogen levels. Here, we report two familial cases of LWD with a large Xp terminal deletion (approximately 943 kb) of distal PAR1 encompassing the SHOX gene. In addition, the proband had mental retardation which appeared to be from recessive inheritance in the family.

Genetic analysis of Rwandan patients with cystic fibrosis-like symptoms: identification of novel cystic fibrosis transmembrane conductance regulator and epithelial sodium channel gene variants

BACKGROUND

The defect in chloride and sodium transport in cystic fibrosis (CF) patients is a consequence of CF transmembrane conductance regulator (CFTR) loss of function and an abnormal interaction between CFTR and the epithelial sodium channel (ENaC). A few patients were described with CF-like symptoms, a single CFTR mutation, and an ENaC mutation.

METHODS

To study African patients with CF-like symptoms and to relate the disease to gene mutations of both CFTR and ENaC genes, we collected clinical data and DNA samples from 60 African patients with a CF phenotype. The CFTR gene was first analyzed in all patients by denaturing high-performance liquid chromatography followed by direct sequencing; whereas, the sodium channel non-voltage-gated 1 alpha (SCNN1A), sodium channel non-voltage-gated 1 beta (SCNN1B), and sodium channel non-voltage-gated 1 gamma (SCNN1G) subunits of the ENaC gene were analyzed by sequencing in the five patients who carried only one CF mutation. The frequency of all identified ENaC variants was established in a control group of 200 healthy individuals and in the 55 CF-like patients without any CFTR mutation.

RESULTS

Three CFTR mutants, including one previously undescribed missense mutation (p.A204T), and a 5T/7T variant were identified in five patients. ENaC gene sequencing in these five patients detected the following eight ENaC variants: c.72T>C and p.V573I in SCNN1A; p.V348M, p.G442V, c.1473 + 28C>T, and p.T577T in SCNN1B; and p.S212S and c.1176 + 30G>C in SCNN1G. In the 55 CF-like patients without any CFTR mutation, we identified five of these eight ENaC variants, including the frequent p.G442V polymorphism, but we did not detect the presence of the p.V348M, p.T577T, and c.1176 + 30G>C ENaC variants. Moreover, these last three ENaC variants, p.V348M, p.T577T, and c.1176 + 30G>C, were not found in the control group.

CONCLUSION

Our data suggest that CF-like syndrome in Africa could be associated with CFTR and ENaC mutations.

Observational Aranesp Survey to Investigate the Q3W Schedule (OASIS): a prospective observational study of treatment of chemotherapy-induced anaemia with every 3 weeks darbepoetin alfa

INTRODUCTION

This prospective observational study examined the adherence to published European guidelines on erythropoiesis-stimulating agents (ESAs) and the pattern of use and effect of darbepoetin alfa (DA) 500 microg once every 3 weeks (Q3W) for the treatment of chemotherapy-induced anaemia (CIA).

MATERIALS AND METHODS

A total of 293 patients were included (263 solid tumour, 30 haematologic malignancy). Their mean age was 63 years, 51% were male, 57% had platinum-based chemotherapy. DA was started at a haemoglobin (Hb) level between 9 and 11 g/dL in 82% of patients.

RESULTS AND DISCUSSION

In an analysis correcting for transfusions, 55% of patients achieved > or =2 g/dL increase in Hb, and a Hb level of >11 g/dL was reached in 81%. Transfusion rate was 27%. Most patients (70%) were treated in a Q3W chemotherapy, and planned synchronisation of chemotherapy and Q3W DA could be maintained in 76%.

CONCLUSION

Adherence to European guidelines for DA treatment was good, and Q3W DA treatment was in synchronisation with Q3W chemotherapy in the majority of the patients, thereby reproducing the findings of a recent phase III study.

Spinocerebellar ataxia type 2 (SCA2): clinical features and genetic analysis

Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurodegenerative disease that results from the expansion of an unstable trinucleotide CAG repeat encoding for a polyglutamine tract. In normal individuals, alleles contain between 14 and 31 CAG repeats, whereas the pathological alleles have more than 35 CAG repeats. The clinical phenotype of SCA2 includes a progressive cerebellar ataxia with additional features such as ophthalmoplegia, extra-pyramidal or pyramidal signs and peripheral neuropathy. We report a SCA2 large African family with several affected individuals. A major pathological allele carrying 43 CAG repeats was identified in the proband. To our knowledge, this is a first report of a SCA disorder described in Central African patients, thus indicating the need to consider this diagnosis in young African ataxic patients.

Goblet cell carcinoid of the appendix: laparoscopic appendectomy or right hemicolectomy?

Goblet cell carcinoids are uncommon tumours with histological features of both adenocarcinoma and carcinoid tumour. They occur predominantly in the appendix and although the malignant potential remains unclear, adenocarcinoids appear to be more aggressive than conventional carcinoids. In this case report, we present a goblet cell carcinoid with laparoscopic operative treatment in two stages. A 43-year-old female patient with constant dullness in the right lower quadrant was diagnosed with acute appendicitis and underwent laparoscopic appendectomy. Macroscopically, a diffusely inflamed appendix was found with no sign of perforation. Histopathological examination revealed a goblet cell carcinoid with characteristics of aggressive behaviour, indicating the need for laparoscopic right hemicolectomy in which, however, neither residual tumour nor metastatic lymph nodes could be found. The postoperative course was uneventful. As they may present the same clinical presentation, pathological diagnosis is required to distinguish goblet cell carcinoid from acute appendicitis. Two-stage surgery for goblet cell carcinoid is advocated in the literature, but the debate still continues as to whether the goblet cell carcinoid should be treated by appendectomy alone, as for most carcinoids, or by right hemicolectomy, as for the appendiceal adenocarcinoma.

Novel SACS mutation in a Belgian family with sacsin-related ataxia

The authors describe the four patients in the first known Belgian family with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). A novel homozygous missense mutation, NM_014363.3: c.3491T>A in exon 9, of the SACS gene was identified in the present family, which results in an original amino acid of methionine to lysine substitution at amino acid residue 1164 (p.M1164K). Although the cardinal clinical features, i.e., spastic ataxia with peripheral neuropathy, in our patients were similar to those in Quebec patients, our patients exhibited some atypical clinical features, e.g., teenage-onset and absence of retinal hypermyelination. The present family is from Wallonia, and there could be shared ethnicity with the families of Charlevoix-Saguenay.

Defining the structure of membrane-bound human blood coagulation factor Va

BACKGROUND

Blood coagulation factor (F) Va is the essential protein cofactor to the serine protease FXa. Factor Va stimulates the thrombin-to-prothrombin conversion by the prothrombinase complex, by at least five orders of magnitude. Factor Va binds with very high affinity to phosphatidylserine containing phospholipid membranes, which allows the visualization of its membrane-bound state by transmission electron microscopy (EM).

METHODS

In this paper we present an averaged three-dimensional structure of FVa molecules attached to phosphatidylserine containing lipid tubes, as determined by EM and single particle analysis. The low-resolution FVa three-dimensional structure is compared with the available atomic models for FVa.

RESULTS

The experimental data are combined with the most suitable atomic model and a membrane-bound FVaEM model is proposed that best fits the protein density defined by EM. In the FVaEM model, the C1 and C2 membrane-binding domains are juxtaposed onto the membrane surface and the model geometries indicate a deeper insertion of both C domains into the lipid bilayer than has been previously suggested.

CONCLUSION

The present structure is a first step towards a higher-resolution experimental structure of a human FVa molecule in its membrane-bound conformation, allowing the visualization of individual domains within FVa and its association with the membrane.

The callipyge mutation and other genes that affect muscle hypertrophy in sheep

Genetic strategies to improve the profitability of sheep operations have generally focused on traits for reproduction. However, natural mutations exist in sheep that affect muscle growth and development, and the exploitation of these mutations in breeding strategies has the potential to significantly improve lamb-meat quality. The best-documented mutation for muscle development in sheep is callipyge (CLPG), which causes a postnatal muscle hypertrophy that is localized to the pelvic limbs and loin. Enhanced skeletal muscle growth is also observed in animals with the Carwell (or rib-eye muscling) mutation, and a double-muscling phenotype has been documented for animals of the Texel sheep breed. However, the actual mutations responsible for these muscular hypertrophy phenotypes in sheep have yet to be identified, and further characterization of the genetic basis for these phenotypes will provide insight into the biological control of muscle growth and body composition.

Ki-67 immunocytochemistry in liquid based cervical cytology: useful as an adjunctive tool?

AIMS

To test the ability of Ki-67 to detect cytological lesions in a screening setting and its use as a surrogate marker of human papillomavirus (HPV) infection.

METHODS

A study of liquid based cytology, HPV DNA testing by MY09/MY11 consensus polymerase chain reaction (PCR), type specific PCRs, and Ki-67 immunocytochemistry on a randomly selected series of 147 patients.

RESULTS

Comparison of the number of Ki-67 immunoreactive cells/1000 cells in the different cytological groups showed that the HSIL group yielded a significantly higher mean count than did the other groups. The number of Ki-67 immunoreactive cells/1000 cells was significantly higher in HPV-16 positive samples than in samples containing infections with other high risk types. Receiver operating characteristic curves indicated a test accuracy (area under curve) of 0.68, 0.72, and 0.86 for atypical squamous cells of undetermined significance (ASCUS), low grade squamous intraepithelial lesions (LSIL), and high grade squamous intraepithelial lesions (HSIL), respectively. Thresholds for 95% sensitivity were 0.07, 0.08, and 0.15 Ki-67 immunopositive cells/1000 cells for ASCUS, LSIL and HSIL, respectively. The threshold for 95% specificity was 1.9 Ki-67 immunopositive cells/1000 cells.

CONCLUSIONS

Ki-67 immunocytochemistry can be applied to liquid based cytology. The accuracy and diagnostic indices of the test are good when compared with those of other techniques. As part of a panel of screening procedures, it could be used as an adjunct to liquid based cytology to identify HSIL, and as a surrogate marker of HPV-16 infection.

Cervical cytological screening and human papillomavirus DNA testing in Flanders

The causal relationship between genital human papillomavirus (HPV) infection and cervical dysplasia/carcinoma has been recognised for some time. The aim of this study was to document the occurrence and distribution of HPV infection in the five provinces of the Flemish region in Belgium and to correlate the HPV DNA test results with the cytological results on simultaneously performed thin layer preparations of cervical cells. Out of a total screened group of 105107 samples, 1978 samples with cytological abnormalities were tested for HPV DNA using the MY09/MY11 consensus PCR. The mean age of the whole group was 36.9 years. The LSIL group, with a mean age of 33.6 years, was significantly younger than the other groups. There was no significant difference in HPV prevalence among the provinces. In four out of five provinces the HPV prevalence reached 100% in high-grade lesions. There is a significant increase in predominance of high-risk HPV types, with increasing abnormal cytology (17.9% WNL < 51.1% ASCUS < 83.8% LSIL < 97.2% HSIL). Three peaks of HPV DNA positivity were observed, a first at 22 yrs (82%), a second at 47 yrs (60%) and a third in women older than 65 yrs (52%). These results shed more light on HPV prevalence in Flanders and show that the MY09/MY11 consensus primer based detection system is very suitable for the detection of HPV infections in Flanders.

Thin-layer liquid-based cervical cytology and PCR for detecting and typing human papillomavirus DNA in Flemish women

The objective of this study was to document the occurrence and to correlate the prevalence of different human papillomavirus (HPV) types with the cytological results on simultaneously performed thin-layer preparations in a large population of Flemish women. During 1 year, 69 290 thin-layer preparations were interpreted using the Bethesda classification system. Using an algorithm for HPV testing based on consensus primers and type-specific PCRs in combination with liquid-based cytology, we determined the occurrence and distribution of 14 different oncogenic HPV types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68). Reflex HPV testing was performed on cytologically abnormal samples and on an age matched randomly selected control group with normal cervical cytology (n=1351). Correlation between cytology, age and prevalence for the 14 different high-risk HPV types is given. There is a significant increase in predominance of high-risk HPV types, with increasing abnormal cytology. Coinfection with multiple HPV types also increased with cytological abnormalities, and was highest in HSIL (16.7%). In Flanders, HSIL was most often associated with HPV types 16, 33, 35, 31, 18 and 51. Using thin-layer liquid-based cytology and PCR to detect HPV, it is feasible to screen large numbers of women.

Mosaicism of Solid Gold supports the causality of a noncoding A-to-G transition in the determinism of the callipyge phenotype

To identify the callipyge mutation, we have resequenced 184 kb spanning the DLK1-, GTL2-, PEG11-, and MEG8-imprinted domain and have identified an A-to-G transition in a highly conserved dodecamer motif between DLK1 and GTL2. This was the only difference found between the callipyge (CLPG) allele and a phylogenetically closely related wild-type allele. We report that this SNP is in perfect association with the callipyge genotype. The demonstration that Solid Gold-the alleged founder ram of the callipyge flock-is mosaic for this SNP virtually proves the causality of this SNP in the determinism of the callipyge phenotype.

Comparative sequence analysis of the imprinted Dlk1-Gtl2 locus in three mammalian species reveals highly conserved genomic elements and refines comparison with the Igf2-H19 region

The Dlk1-Gtl2 domain on mouse chromosome 12 contains reciprocally imprinted genes with the potential to contribute to our understanding of common features involved in imprinting control. We have sequenced this conserved region in the mouse and sheep and included the human sequence in a three species comparison. This analysis resulted in a precise conservation map and identification of highly conserved sequence elements, some of which we have shown previously to be differentially methylated in the mouse. Additionally, this analysis facilitated identification of a CpG-rich tandem repeat array located approximately 13-15 kb upstream of Gtl2. Furthermore, we have identified a third imprinted transcript that overlaps with the last Dlk1 exon in the mouse. This transcript lacks a conserved open reading frame and is probably generated by cleavage of extended Dlk1 transcripts. Because Dlk1 and Gtl2 share many of the imprinting properties of the well-characterized Igf2-H19 domain, it has been proposed that the two regions may be regulated in the same way. Comparative genomic examination of the two domains indicates that although there are similarities, other features are very different, including the location of conserved CTCF-binding sites, and the level of conservation at regulatory regions.

Human-ovine comparative sequencing of a 250-kb imprinted domain encompassing the callipyge (clpg) locus and identification of six imprinted transcripts: DLK1, DAT, GTL2, PEG11, antiPEG11, and MEG8

Two ovine BAC clones and a connecting long-range PCR product, jointly spanning approximately 250 kb and representing most of the MULGE5-OY3 marker interval known to contain the clpg locus, were completely sequenced. The resulting genomic sequence was aligned with its human ortholog and extensively annotated. Six transcripts, four of which were novel, were predicted to originate from within the analyzed region and their existence confirmed experimentally: DLK1, DAT, GTL2, PEG11, antiPEG11, and MEG8. RT-PCR experiments performed on a range of tissues sampled from an 8-wk-old animal demonstrated the preferential expression of all six transcripts in skeletal muscle, which suggests that they are under control of common regulatory elements. The six transcripts were also shown to be subject to parental imprinting: DLK1, DAT, and PEG11 were shown to be paternally expressed and GTL2, antiPEG11, and MEG8 to be maternally expressed.

Laparoscopic inguinal hernia repair: review of 6 years experience

Since 6 years, the totally extraperitoneal laparoscopic hernia repair has become our procedure of choice to manage inguinal hernia in adult patients, especially for bilateral hernias and recurrences after classical anterior repair. Between March 1993 and March 1999, 976 patients underwent 1259 hernia repairs by an endoscopic total extraperitoneal approach. A large polypropylene prosthesis (15 x 15 cm) is placed and covers all potential defects. Follow-up on patients ranged from 6 to 79 months (mean, 39 months). Per- and postoperative morbidity and complications were acceptable (8.4%) and included conversion to open surgery (0.4%), bleedings (0.3%), urinary retention (4.2%), seromas (2.7%), neuralgias (0.2%), vague persistent groin discomfort (0.4%), orchitis (0.08%) and sigmoido-cutaneous fistula (0.08%). Recurrence rate so far is 0.1%. This retrospective study shows that the totally extraperitoneal repair for inguinal hernia should have a promising future because of low morbidity and low recurrence rate.

The callipyge mutation enhances the expression of coregulated imprinted genes in cis without affecting their imprinting status

The callipyge (CLPG) phenotype (from kappa(alpha)lambda(iota), "beautiful," and pi(iota)gamma(epsilon), "buttocks") described in sheep is an inherited muscular hypertrophy that is subject to an unusual parent-of-origin effect referred to as polar overdominance: only heterozygous individuals having inherited the CLPG mutation from their sire exhibit the muscular hypertrophy. The callipyge (clpg) locus was mapped to a chromosome segment of approximately 400 kb (refs. 2-4), which was shown to contain four genes (DLK1, GTL2, PEG11 and MEG8) that are preferentially expressed in skeletal muscle and subject to parental imprinting in this tissue. Here we describe the effect of the CLPG mutation on the expression of these four genes, and demonstrate that callipyge individuals have a unique expression profile that may account for the observed polar overdominance.

Fine-mapping and construction of a bovine contig spanning the ovine callipyge locus

The callipyge (CLPG) gene was fine-mapped by linkage analysis to a 4.6-cM chromosome interval on distal ovine OAR18q, flanked by microsatellite markers IDVGA30 and OY3. The OAR18q linkage map and human HSA14q transcript map were aligned by genotyping two bovine-hamster whole-genome radiation hybrid panels with the microsatellite markers, as well as with sequences corresponding to HSA 14q genes. Using Type I loci mapping to the IDVGA30-OY3 interval as anchor points, we have constructed a 1.4-Mb bovine BAC contig containing the IDVGA30-OY3 interval. We demonstrate that the IDVGA30-OY3 interval spans approximately 770 kb and contains at least four genes: YY1, WARS, DLK1, and GTL2.

Construction and characterization of an ovine BAC contig spanning the callipyge locus

We describe the construction of an ovine BAC contig spanning a 4.6 centimorgan (cM) chromosome segment known to contain the callipyge (CLPG) locus. The contig comprises 21 ovine BAC clones jointly covering approximately 900 kilobases (Kb). Two gaps in the BAC contig, spanning 10 and 7.5 Kb, respectively, were bridged by long range PCR. The corresponding chromosome region was shown to be characterized by an unusually low Kb to cM ratio (164 Kb/cM) and a high density of Not1 sites (1:126 Kb) possibly reflecting a high gene density in the corresponding chromosome region. Equivalent amplification of 64 sequence tagged sites spanning the corresponding region from homozygous +/+ and CLPG/CLPG individuals disproves the hypothesis of a major deletion causing the CLPG mutation.

Evaluation of tumour angiogenesis as a prognostic marker in malignant mesothelioma

Angiogenesis plays an important role in the growth, progression, and metastasis of solid tumours. Malignant mesothelioma (MM) of the pleura is a highly invasive tumour with a poor prognosis. In the present study, microvascular quantification was undertaken on 25 specimens of mesothelioma and 15 specimens of non-neoplastic mesothelium (NNM), by staining for the antigens CD34 and CD31. Areas of highest intratumoural microvascular density (IMD) were identified and counted either manually (mIMD) or on a computerized image analysis system (CIAS; iIMD). The two IMDs were significantly correlated with each other (r = 0.736; P < 0.001). The average IMD for MM was significantly (P < 0.001) higher than in NNM. Moreover, each unit increment in iIMD for MM, when regarded as a continuous variable, was significantly (P = 0.001) associated with an increased hazard of about 4 per cent. When regarded as a categorical variable, the patients in the highest tertile (> 58 vessels/field) had a significantly (P < 0.01; log-rank test) shorter survival than patients in the lowest tertile (< 45 vessels/field). This association was independent of the age of the patient and of the histological type or grade of the MM. No association was noted with p53 immunoexpression. Although the mean vascular area of blood vessels measured on the CIAS did not correlate with survival, assessment of IMDs can be an important independent prognostic indicator in malignant mesothelioma.

WT1 mutation in malignant mesothelioma and WT1 immunoreactivity in relation to p53 and growth factor receptor expression, cell-type transition, and prognosis

The Wilms tumour 1 (WT1) gene is believed to contribute to the growth and differentiation of certain tissues, including mesothelium. This study assessed WT1 gene status by mutational screening in 42 malignant mesotheliomas (MMs) and 3 MM cell lines and detected two tumours with identical heterozygous single nucleotide deletions in intron 7, with no apparent consequence for WT1 function. Furthermore, the expression pattern of the WT1 gene was studied in MMs and related lesions using three anti-WT1 monoclonal antibodies (MAbs). Strong to moderate nuclear immunoreactivity was noted in MM in situ (54/56), cultured mesothelioma cells (4/5), and hyperplastic and normal pleural (non-neoplastic, NNM) specimens. WT1 immunoreactivity was absent in all primary tumours of lung and in pleural metastases from adenocarcinomas of breast and colon; immunoreactivity was present in pleural metastases from renal carcinomas, melanomas, and papillary carcinomas of the ovary. Expression of the WT1 protein in MM was not correlated with survival. Coordinate expression of the WT1 protein and its putative transcriptional target genes was determined by correlating WT1 immunostaining with epidermal growth factor receptor (EGF-R) and insulin-like growth factor 1 receptor (IGF-1R) expression on MM and NNM; no significant correlation was found, irrespective of p53 expression status. Finally, the putative involvement of WT1 in cell-type transition was supported by this study, in that epithelial mesothelioma showed the strongest WT1 immunoreactivity while sarcomatous mesothelioma showed the least.

Glutathione S-transferase expression in malignant mesothelioma and non-neoplastic mesothelium: an immunohistochemical study

Expression of the glutathione S-transferase (GST) subclasses alpha, mu and pi was investigated immunohistochemically in 20 normal or hyperplastic mesothelium and in 57 malignant mesothelioma cases. These results were correlated with survival and also with P-170 glycoprotein expression. Nearly all the non-neoplastic mesothelium cases were positive for GST alpha and pi. About half of the non-neoplastic cases were positive for mu. Twenty-nine (51%) malignant mesotheliomas were positive for at least one of the GST species; 21 (37%) showed immunoreactivity for alpha, 18 (31.5%) for mu and 21 (37%) for pi. A total of 54 mesothelioma cases displayed immunoreactivity for the P-170 glycoprotein. For GST pi and GST mu, a statistical significance between expression and increased survival was found (respectively P = 0.012 and 0.024) while for GST alpha no significance was found. The results of this study demonstrate that expression of GST pi correlates positively with increased survival in malignant mesothelioma. It is also concluded that, in mesothelioma, GST and P-170 glycoprotein may contribute to the resistance to cytotoxic drugs frequently observed in these tumours. No correlation between GST and P-170 expression was demonstrated.

Evaluation and prognostic value of DNA content and of morphometric parameters in malignant mesothelioma using digital image analysis

Fifty-seven cases of malignant mesothelioma were analyzed for nuclear diameter, DNA content and ploidy-related parameters, using Feulgen stained paraffin sections with a digital imaging analysis system. Thirty cases had a mean nuclear diameter > 7 microns and 31 cases were classified as near-diploid. A statistically significant correlation between survival and the mean nuclear diameter (P = 0.0006) and between survival and DNA index (P = 0.007) was obtained. For other DNA content parameters (proliferation index, 5c exceeding rate), only one of the two statistical tests showed a significant correlation with survival while the other test was of borderline significance. In this malignant mesothelioma population, the prognosis for patients with the epithelial type was better than for those with sarcomatous tumours (P = 0.01). In this population of patients, about half of the malignant mesotheliomas were aneuploid. The mean nuclear diameter, DNA index analysis and proliferation index analysis of the tumour cells on Feulgen stained paraffin sections can be used as independent prognostic parameters.

Stereological evaluation of malignant mesothelioma versus benign pleural hyperplasia

The differential diagnosis between malignant mesothelioma and benign pleural hyperplasia constitutes a well-known problem. In the present study we examined unbiased stereological techniques to assess the mean nuclear volume (MNV) using the point-sampled intercepts (PSI) in 37 cases of malignant mesothelioma and in 28 cases of benign pleural hyperplasia. Neither the use of different fixatives nor the histological type of malignant mesothelioma produced any significant difference on the measured nuclear volume. The differences observed between the MNV data obtained from benign pleural hyperplasia and those from any of the three types of malignant mesothelioma were found to be highly significant. All lesions with an MNV larger than 250 microns3 were found in our study to correspond to the malignant mesothelioma type, while an MNV that was smaller than 200 microns3 could only be detected in benign specimens. These observations lead us to propose the MNV measurement using PSI as an additional tool to enhance the differential diagnosis of malignant mesothelioma versus benign pleural hyperplasia.

Immunoreactivity for p53 and mdm2 and the detection of p53 mutations in human malignant mesothelioma

Previous immunohistochemical studies on malignant mesothelioma with antibodies recognizing both the wild and the mutant types of the p53 protein have shown immunoreactivity in 25-70% of cases. This study was designed to determine whether there is immunoreactivity for p53 and mdm2 protein in malignant mesothelioma and to correlate p53 expression with the detection of mutations in p53 at DNA level. In 10 of 15 cases there was immunoreactivity for p53. In 6 of these cases immunoreactivity for mdm2 was also detected. In one p53-immunonegative case, a mutation of the p53 gene resulting in a stop codon was found. These results suggest that mdm2 might be involved in the inhibition of p53 in malignant mesothelioma. Also, these data suggest the existence of other proteins than mdm2 that may associate with p53.

[Transient erythroblastopenia in 4 children]

In four patients, all girls, aged 2, 3.5, 4 and 5 years, transient erythroblastopenia was diagnosed. The children were presented because of acute pallor. The haemoglobin levels were 2.8 to 5.0 mmol/l. After 3 weeks all patients had recovered or were recovering with increasing haemoglobin values. Three of the four patients needed one blood transfusion. In two patients there was evidence of a parvovirus B19 infection. Transient erythroblastopenia is mostly seen in patients aged 1-4 years. Most cases are postinfectious and there is evidence that human parvovirus B19 is responsible for many cases. In the very young child the differential diagnosis from Blackfan-Diamond anaemia may be very difficult.

Immunoreactivity for c-fos and c-myc protein with the monoclonal antibodies 14E10 and 6E10 in malignant mesothelioma and non-neoplastic mesothelium of the pleura

We studied immunoreactivity for c-fos protein and c-myc protein in malignant mesothelioma (36 cases) and non-neoplastic pleural mesothelium (45 cases) using the murine monoclonal antibodies 14E10 and 6E10. All malignant mesotheliomas and cases with non-neoplastic mesothelium exhibited not only nuclear but also cytoplasmic immunoreactivity for c-fos and c-myc protein in the majority of mesothelial cells. There was no statistically significant difference between the various mesothelioma subtypes or between neoplastic and non-neoplastic mesothelium for c-fos protein immunoreactivity (p > 0.05). There was statistically significant difference between neoplastic and non-neoplastic mesothelium for c-myc protein immunoreactivity (p < 0.01). We conclude that immunoreactivity for c-fos and c-myc protein is present in both non-neoplastic and neoplastic mesothelium, but that a higher proportion of neoplastic mesothelial cells are immunoreactive for c-myc protein when compared with non-neoplastic mesothelium.