BRCA1, BRCA2 and PALB2 mutations and CHEK2 c.1100delC in different South African ethnic groups diagnosed with premenopausal and/or triple negative breast cancer.

BACKGROUND: Current knowledge of the aetiology of hereditary breast cancer in the four main South African population groups (black, coloured, Indian and white) is limited. Risk assessments in the black, coloured and Indian population groups are challenging because of restricted information regarding the underlying genetic contributions to inherited breast cancer in these populations. We focused this study on premenopausal patients (diagnosed with breast cancer before the age of 50; n = 78) and triple negative breast cancer (TNBC) patients (n = 30) from the four South African ethnic groups. The aim of this study was to determine the frequency and spectrum of germline mutations in BRCA1, BRCA2 and PALB2 and to evaluate the presence of the CHEK2 c.1100delC allele in these patients. METHODS: In total, 108 South African breast cancer patients underwent mutation screening using a Next-Generation Sequencing (NGS) approach in combination with Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large rearrangements in BRCA1 and BRCA2. RESULTS: In 13 (12 %) patients a deleterious mutation in BRCA1/2 was detected, three of which were novel mutations in black patients. None of the study participants was found to have an unequivocal pathogenic mutation in PALB2. Two (white) patients tested positive for the CHEK2 c.1100delC mutation, however, one of these also carried a deleterious BRCA2 mutation. Additionally, six variants of unknown clinical significance were identified (4 in BRCA2, 2 in PALB2), all in black patients. Within the group of TNBC patients, a higher mutation frequency was obtained (23.3 %; 7/30) than in the group of patients diagnosed before the age of 50 (7.7 %; 6/78). CONCLUSION: This study highlights the importance of evaluating germline mutations in major breast cancer genes in all of the South African population groups. This NGS study shows that mutation analysis is warranted in South African patients with triple negative and/or in premenopausal breast cancer.

Flemish network on rare connective tissue diseases (CTD): patient pathways in systemic sclerosis. First steps taken.

Despite the low prevalence of each rare disease, the total burden is high. Patients with rare diseases encounter numerous barriers, including delayed diagnosis and limited access to high-quality treatments. In order to tackle these challenges, the European Commission launched the European Reference Networks (ERNs), cross-border networks of healthcare providers and patients representatives. In parallel, the aims and structure of these ERNs were translated at the federal and regional levels, resulting in the creation of the Flemish Network of Rare Diseases. In line with the mission of the ERNs and to ensure equal access to care, we describe as first patient pathways for systemic sclerosis (SSc), as a pilot model for other rare connective and musculoskeletal diseases. Consensus was reached on following key messages: 1. Patients with SSc should have multidisciplinary clinical and investigational evaluations in a tertiary reference expert centre at baseline, and subsequently every three to 5 years. Intermediately, a yearly clinical evaluation should be provided in the reference centre, whilst SSc technical evaluations are permissionably executed in a centre that follows SSc-specific clinical practice guidelines. In between, monitoring can take place in secondary care units, under the condition that qualitative examinations and care including interactive multidisciplinary consultations can be provided. 2. Patients with early diffuse cutaneous SSc, (progressive) interstitial lung disease and/or pulmonary arterial hypertension should undergo regular evaluations in specialised tertiary care reference institutions. 3. Monitoring of patients with progressive interstitial lung disease and/or pulmonary (arterial) hypertension will be done in agreement with experts of ERN LUNG.

[Use of patient radiation shielding in diagnostic and interventional radiology]. / Einsatz von Patienten-Strahlenschutzmitteln in der diagnostischen und interventionellen Radiologie.

The use of patient contact shielding provides an opportunity to reduce patient radiation exposure. Recently, the use has been the subject of controversy. The Radiation Protection Committee has published a recommendation on the use of patient radiation shields by considering the recent findings on dose savings but also the risks of incorrect use. In this article, a specification for the more frequently used types of X­ray examination is given, which describes whether and which radiation contact shielding should be used. This is accompanied by a rationale for the use or non-use of patient radiation protection agents. Problems and possible errors are explained, as well as how to deal with special situations such as pregnant women and children.

Mutation analysis of RAD51D in non-BRCA1/2 ovarian and breast cancer families.

BACKGROUND: Recent data show that mutations in RAD51D have an aetiological role in ovarian carcinoma, yet mutations do not appear to be associated with an increased risk for breast cancer. We studied ovarian and breast cancer families having at least one woman affected by ovarian carcinoma, to assess the importance of RAD51D mutations in such families. METHODS: The coding region of the RAD51D gene was analysed in 175 BRCA1/2-negative families with family histories of both ovarian and breast cancer ascertained from two Canadian and two Belgian institutions. RESULTS: We identified one previously reported deleterious mutation, p.Arg186(*) (c.556C>T), and two novel variants; missense substitution p.Cys119Arg and an intronic variant c.83-26A>G. p.Arg186(*) segregated with the disease in the family and two ovarian carcinomas available for analysis showed loss of the wild-type allele, but the novel variants are likely neutral. CONCLUSION: RAD51D should be included in genetic screening of ovarian cancer families that do not have BRCA1/BRCA2 mutations. We show that mutations are more likely to be found in families with two or more ovarian cancers, or in probands with first-degree relatives with ovarian cancer, and we feel testing should be preferentially offered to affected women from such families.

Evaluation of RAD51C as cancer susceptibility gene in a large breast-ovarian cancer patient population referred for genetic testing.

Despite extensive analysis of the BRCA1 and BRCA2 genes, germline mutations are detected in <20% of families with a presumed genetic predisposition for breast and ovarian cancer. Recent literature reported RAD51C as a new breast cancer susceptibility gene. In this study, we report the analysis of 410 patients from 351 unrelated pedigrees. All were referred for genetic testing and we selected families with at least one reported case of ovarian cancer in which BRCA1&2 mutations were previously ruled out. We analyzed the coding exons, intron-exons boundaries, and UTRs of RAD51C. Our mutation analysis did not reveal any unequivocal deleterious mutation. In total 12 unique sequence variations were identified of which two were novel. Our study and others suggest a low prevalence of RAD51C mutations with an exception for some founder populations. This observation is in favor of the rare allele hypothesis in the debate over the nature of the genetic contribution to individual susceptibility to breast and ovarian cancer and further genome-wide studies in high risk families are warranted.

Numerical deconvolution to enhance sharpness and contrast of portal images for radiotherapy patient positioning verification.

PURPOSE: The quality of megavoltage clinical portal images is impaired by physical and geometrical effects. This image blurring can be corrected by a fast numerical two-dimensional (2D) deconvolution algorithm implemented in the electronic portal image device. We present some clinical examples of deconvolved portal images and evaluate the clinical advantages achieved by the improved sharpness and contrast. MATERIALS AND METHODS: The principle of numerical 2D image deconvolution and the enhancement of sharpness and contrast thereby achieved are shortly explained. The key concept is the convolution kernel K(x,y), the mathematical equivalent of the smearing or blurring of a picture, and the computer-based elimination of this influence. RESULTS: Enhancements of sharpness and contrast were observed in all clinical portal images investigated. The images of fine bone structures were restored. The identification of organ boundaries and anatomical landmarks was improved, thereby permitting a more accurate comparison with the x-ray simulator radiographs. The visibility of prostate gold markers is also shown to be enhanced by deconvolution. CONCLUSION: The blurring effects of clinical portal images were eliminated by a numerical deconvolution algorithm that leads to better image sharpness and contrast. The fast algorithm permits the image blurring correction to be performed in real time, so that patient positioning verification with increased accuracy can be achieved in clinical practice.

Response of diamond detectors in ultra-high dose-per-pulse electron beams for dosimetry at FLASH radiotherapy.

Objective.With increasing investigation of the so-called FLASH effect, the need for accurate real time dosimetry for ultra-high dose rates is also growing. Considering the ultra-high dose-per-pulse (DPP) necessary to produce the ultra-high dose rates for investigations of the FLASH effect, real time dosimetry is a major challenge. In particular, vented ionization chambers, as used for dosimetry in conventional radiotherapy, show significant deviations from linearity with increasing DPP. This is due to recombination losses in the sensitive air volume. Solid state detectors could be an alternative. Due to their good stability of the response with regard to the accumulated dose, diamond detectors such as the microDiamond could be suitable here. The aims of this work are to investigate the response of microDiamond and adapted microDiamond prototypes in ultra-high DPP electron beams, to understand the underlying effects and to draw conclusions for further detector developments.Approach.For the study, an electron beam with a DPP up to 6.5 Gy and a pulse duration of 2.5µs was used to fulfill the conditions under which the FLASH effect was observed. As a dose rate-independent reference, alanine dosimeters were used.Main Results.It has been shown that the commercially available microDiamond detectors have limitations in terms of linearity at ultra-high DPP. But this is not an intrinsic limitation of the detector principle. The deviations from linearity were correlated with the series resistance and the sensitivity. It could be shown that the linear range can be extended towards ultra-high DPP range by reducing the sensitivity in combination with a low series resistance of the detectors.Significance.The work shows that synthetic single crystal diamond detectors working as Schottky photodiodes are in principle suitable for FLASH-RT dosimetry at electron linear accelerators.

A long-term neuropsychological evaluation in Fabry disease.

Fabry disease (FD) is a X-linked multi-systemic metabolic disorder with mainly renal, cardiac and neurological dysfunction. The neuropsychological impact is still unclear, with previous study results ranging from disturbance of speed of information processing and executive functions to a normal cognitive profile. The aim of our study was to gain further insight into the neuropsychological involvement of FD. Patients with genetically proven FD were enrolled at the Ghent University Hospital by their treating neurologist. We evaluated the cognitive status of each patient by a thorough neuropsychological test battery and these exact same neuropsychological assessments were repeated after a follow-up period of 2-4 years and at a second follow-up moment 1-4 years after the first follow-up. Thirteen patients with FD were included (8 female) with mean age of 41.5 years (SD ± 13.9) at baseline. All patients had normal neuropsychological test results on the subtests included in the cognitive battery at baseline, according to age-, gender- and education matched normative data. At the first follow-up moment (2-4 years after baseline), six patients were included (3 male), mean age 45.3 years. At the second follow-up (1-4 years after first follow-up), four patients (2 male) were included, with mean age 45 years. Both at the first and second follow-up moments, all patients obtained normal scores on the subtests. The cognitive functioning appeared to be in the normal range at baseline and did not decline over a follow-up period of 3-8 years, suggesting that cognition in FD patients may be well-preserved in time.

Copy number alterations and copy number variation in cancer: close encounters of the bad kind.

Recent studies have unveiled copy number variants (CNVs) as an important source of genetic variation. Many of these CNVs contain coding sequences, which have been shown to be dosage sensitive. Evidence is accumulating that certain CNVs have impact on susceptibility to human diseases such as HIV infection and autoimmune diseases, as well as on adaptability to environmental conditions or nutrition. The possible role and impact of CNVs on cancer development and progression is only now emerging. In this review we look into the role of CNVs and their associated genomic structural features in relation to the formation of chromosome alterations in cancer cells and evolutionary genomic plasticity, as well as the de novo occurrence of known or putative CNVs as somatic events during oncogenesis. The role of germline CNVs in cancer predisposition is still largely unexplored. A number of observations seem to warrant the importance of further studies to elucidate the impact of these variants in the early steps of carcinogenesis.

Clinical, cytogenetic and molecular characteristics of 14 T-ALL patients carrying the TCRbeta-HOXA rearrangement: a study of the Groupe Francophone de Cytogénétique Hématologique.

Recently, we and others described a new chromosomal rearrangement, that is, inv(7)(p15q34) and t(7;7)(p15;q34) involving the T-cell receptor beta (TCRbeta) (7q34) and the HOXA gene locus (7p15) in 5% of T-cell acute lymphoblastic leukemia (T-ALL) patients leading to transcriptional activation of especially HOXA10. To further address the clinical, immunophenotypical and molecular genetic findings of this chromosomal aberration, we studied 330 additional T-ALLs. This revealed TCRbeta-HOXA rearrangements in five additional patients, which brings the total to 14 cases in 424 patients (3.3%). Real-time quantitative PCR analysis for HOXA10 gene expression was performed in 170 T-ALL patients and detected HOXA10 overexpression in 25.2% of cases including all the cases with a TCRbeta-HOXA rearrangement (8.2%). In contrast, expression of the short HOXA10 transcript, HOXA10b, was almost exclusively found in the TCRbeta-HOXA rearranged cases, suggesting a specific role for the HOXA10b short transcript in TCRbeta-HOXA-mediated oncogenesis. Other molecular and/or cytogenetic aberrations frequently found in subtypes of T-ALL (SIL-TAL1, CALM-AF10, HOX11, HOX11L2) were not detected in the TCRbeta-HOXA rearranged cases except for deletion 9p21 and NOTCH1 activating mutations, which were present in 64 and 67%, respectively. In conclusion, this study defines TCRbeta-HOXA rearranged T-ALLs as a distinct cytogenetic subgroup by clinical, immunophenotypical and molecular genetic characteristics.

2007 recommendations of the ICRP change basis for estimation of the effective dose: what is the impact on radiation dose assessment of patient and personnel?

PURPOSE: In radiation protection regulations the algorithm for effective dose calculation is based on Publication 60 (1990) of the International Commission on Radiological Protection (ICRP). The modifications to the tissue weighting factors in Publication 103 (2007) of the ICRP will affect the present methodology of calculating the effective dose and will also have an impact on its assessment. This paper evaluates circumstances under which the application of the new model yields relevant dose differences compared to the prevailing model. MATERIALS AND METHODS: Effective doses were calculated and compared from the measured organ doses according to ICRP 60 and ICRP 103, respectively. The measurements of patient doses were carried out with an anthropomorphic phantom for thoracic and coronary CT examinations. Exposure of radiological personnel was measured based on the geometry of angiographic examinations using two anthropomorphic phantoms. RESULTS: The change of the weighting factor for the breast from 0.05 to 0.12 leads to a noticeable increase in the effective dose for thoracic (21 %) and coronary (31 %) CT examinations. Calculating sex-specific effective doses based on ICRP 60, the dose for coronary CT examination for women is 1.7 times higher than for men. Based on ICRP 103, the difference between female and male doses increases to a factor of 3.3. Due to the consideration of organs in the head and neck region as introduced in ICRP 103, for angiography the personnel is exposed to 24 - 50 % and 38 - 142 % higher doses with and without thyroid protection, respectively. Thereby, the official personal dosimetry will underestimate the effective dose according to ICRP 103 by a factor of 1.6 - 2.4 with thyroid protection and 1.1 - 1.4 without thyroid protection. CONCLUSION: The revision of the parameters for effective dose calculation leads to higher doses and greater sex-specific differences for radiological examinations involving exposure of the breast. This effect should be considered when justifying any radiological examination. For the personnel, the new model results in higher effective doses due to increased emphasis on the organs in the head and neck region. Hence to optimize radiation protection of personnel, the use of radiation-protective shielding for this region becomes more important.

Conversion coefficients for the estimation of effective doses in intraoral and panoramic dental radiology from dose-area product values.

Conversion coefficients for the estimation of effective doses in intraoral and panoramic dental radiology from dose-area product (DAP) values were determined by measuring organ-absorbed doses and the corresponding DAP values. Measurements were performed for all standard intraoral radiological projections and standard panoramic examination at different exposure parameters. Organ-absorbed doses were measured using thermoluminescent detectors and an adult anthropomorphic phantom specially designed for dosimetric study in dental radiology. Different techniques for the calculation of effective doses were evaluated. Conversion coefficients derived from this study range from 0.008 to 0.132 microSv mGy(-1) cm(-2) for intraoral radiography and 0.055 to 0.238 microSv mGy(-1) cm(-2) for panoramic radiography.

OCCUPATIONAL EXPOSURE FROM F-18-FDG PET/CT: IMPLEMENTATION TO ROUTINE CLINICAL PRACTICE.

The purpose of this study was to assess the occupational radiation exposure arising from positron emission tomography combined with X-ray computed tomography (PET/CT) procedures. From 2009 through the end of 2014, in a team of six technologists, personal dosimetry was performed using electronic personal dosemeters and film badge dosemeters. The technologists registered the separate exposure after each PET/CT operational step, which included radiopharmaceutical arrival, dispensing in individual syringes, injection and patient positioning.From the total of 3024 PET/CT procedures, 2142 were available for analysis. The personal dose equivalent for the technologists performing PET/CT ranged from 11.5 nSv/MBq to 23.8 nSv/MBq. Whole-body radiation dose originated mainly from radiopharmaceutical injection (41.5%) and patient positioning (51.1%). The sources of occupational exposure were successfully identified for PET/CT procedures. Record keeping using on-site occupational dosimetry is a useful tool for exposure optimisation.

Patient positioning verification for proton therapy using proton radiography.

We present a proof of principle, experimental validation of the potential of proton 'Range Probes' (RP) for patient positioning verification in proton therapy. In this work, we have evaluated experimentally the accuracy of RP by using tissue-like samples and an in-house developed multilayer ionization chamber (MLIC). In addition we build on our previous, simulation based work to present first experimental measurements of RP through anthropomorphic phantoms to detect either rotational or translational positioning errors. For this, a technique has been proposed to characterize the residual integral depth dose curve (RIDDC) after range mixing. This parametrization has been used to evaluate the similarity between Monte Carlo calculated error scenarios of the database and the measured RIDDC, while considering the intrinsic uncertainties of both modalities in order to deduce the positioning error. Finally, the additional dose applied to the patient when using clinical RP with known fluence has been estimated by measuring the local dose of a single RP. In tissue phantoms, the prediction accuracy of the water equivalent path length was 0.70%, with the highest deviations being found in low density samples (up to 5.67%). In addition, the results of the patient positioning verification measurements demonstrated that using carefully selected RPs, 1D translational or rotational errors could be detected with an accuracy of 1 mm and 2°, respectively, and that these would be associated with a low additional dose burden to the patient. In summary, these promising results suggest that the RP method could be a simple, fast and low-dose tool for verifying patient set-up during proton therapy treatment.

Molecular cytogenetic study of 126 unselected T-ALL cases reveals high incidence of TCRbeta locus rearrangements and putative new T-cell oncogenes.

Chromosomal aberrations of T-cell receptor (TCR) gene loci often involve the TCRalphadelta (14q11) locus and affect various known T-cell oncogenes. A systematic fluorescent in situ hybridization (FISH) screening for the detection of chromosomal aberrations involving the TCR loci, TCRalphadelta (14q11), TCRbeta (7q34) and TCRgamma (7p14), has not been conducted so far. Therefore, we initiated a screening of 126 T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma cases and 19 T-ALL cell lines using FISH break-apart assays for the different TCR loci. Genomic rearrangements of the TCRbeta locus were detected in 24/126 cases (19%), most of which (58.3%) were not detected upon banding analysis. Breakpoints in the TCRalphadelta locus were detected in 22/126 cases (17.4%), whereas standard cytogenetics only detected 14 of these 22 cases. Cryptic TCRalphadelta/TCRbeta chromosome aberrations were thus observed in 22 of 126 cases (17.4%). Some of these chromosome aberrations target new putative T-cell oncogenes at chromosome 11q24, 20p12 and 6q22. Five patients and one cell line carried chromosomal rearrangements affecting both TCRbeta and TCRalphadelta loci. In conclusion, this study presents the first inventory of chromosomal rearrangements of TCR loci in T-ALL, revealing an unexpected high number of cryptic chromosomal rearrangements of the TCRbeta locus and further broadening the spectrum of genes putatively implicated in T-cell oncogenesis.

Characterization of the radiation quality of 60Co therapy units by the fraction of air kerma attributable to scattered photons.

In this work we present a new parameter for characterizing the emitted photon spectra of (60)Co radiotherapy units. It is intended to propose this parameter for the revised DIN standard 6809-1. In the previous DIN regulation, it had been sufficient to state the nature of the radioactive material within the source. However, scatter processes within the radioactive material as well as the source housing and the collimator system influence the shape of the photon spectrum, with a noticeable contribution in the low-energy portion. The fraction of the air kerma for a given distance from the source, position and beam size in air comprising all contributions by scattered photons up to an upper energy limit for the emitted spectrum from (60)Co decay, will be proposed as a typical parameter. The new quantity, which is termed the 'fraction of air kerma attributable to scattered photons', P(E)(Scatter), has been calculated for E = 1.17 MeV and compared for four different Monte Carlo-simulated spectra of used (60)Co devices. Not included in this new formalism is the air kerma contribution by scattered photons in between the two lines of the (60)Co spectrum. A simple measurement procedure based on the signal ratio of two Farmer chamber detectors with different wall materials is discussed and its feasibility shown.

Acquired chromosomal rearrangements targeting selected transcription factors: contribution of molecular cytogenetic and expression analyses to the identification of clinically and biologically relevant subgroups in hematological malignancies.

In leukemias chromosomal aberrations, balanced translocations in particular, play a critical role in the oncogenic process. The characterization of these chromosomal alterations was crucial to the discovery of the genes implicated in leukemogenesis, as the chromosomal breakpoints indicated their genomic localization. In addition, these molecular defects may serve as targets for diagnostic essays and can have a major prognostic value. Finally, the characterization of the deregulated cellular pathways potentially identifies targets for therapeutic intervention. In this paper we summarize our efforts to expand the current knowledge of the diagnostic, prognostic or biological significance of selected chromosomal aberrations identified in M-FISH studies. First, we illustrated the power of M-FISH in dissecting complex chromosomal aberrations in myeloid neoplasms. MLL amplification was defined as a clinical entity characterized by adverse prognosis and within the multitude and variety of chromosomal rearrangements a pattern of a limited number of cytogenetic subclasses was discerned. In leukemias characterized by 11q23 amplification, we described the amplicon and confirmed MLL, in addition to DDX6, as a principal amplification target. Molecular characterization of a large series of unselected sporadic and recurrent 3q26 rearranged leukemias confirmed the decisive role of ectopic EVI1 expression in these malignancies. We contributed to an extensive analysis of the phenotypical and prognostic features of T-ALL characterized by HOX11L2 expression and identified HOX11L2 overexpression as one of the most frequent genetic defects in childhood T-ALL, associated with intermediate prognosis. Finally, we designed and validated diagnostic tools for the detection of the t(9;14) (p13;q34) resulting in PAX5 overexpression and convincingly associated the presence of this rearrangement to high-grade morphology and karyotype complexity. In conclusion, the series of investigations presented here clearly illustrate the benefits of M-FISH as molecular tool for the dissection and characterization of complex and cryptic rearrangements. The subsequent reports demonstrate the utility of molecular cytogenetics and expression analyses to the clinical management of patients diagnosed with hematological malignancies.

Dose-area product measurements and determination of conversion coefficients for the estimation of effective dose in dental lateral cephalometric radiology.

A study has been carried out to propose diagnostic reference levels (DRLs) for lateral cephalometric radiology in Germany based on the dose-area product (DAP). DRLs were proposed separately for child and adult exposure settings which are 26.4 and 32.6 mGy cm2, respectively. Organ absorbed doses from lateral cephalometric radiology were also measured using thermoluminescence detectors (TLDs) and an adult anthropomorphic phantom specially design for dosimetric study in dental radiology. Effective doses were then calculated using three different techniques where the salivary gland and brain tissue were given different weighting factors. Conversion coefficients for estimating effective dose from DAP value derived in this study range from 0.042 to 0.149 microSv/mGy cm2.

Radiation exposure and dose evaluation in intraoral dental radiology.

In this study, dose area product measurements have been performed to propose diagnostic reference levels (DRLs) in intraoral dental radiology. Measurements were carried out at 60 X-ray units for all types of intraoral examinations performed in clinical routine. The third quartile values calculated range from 26.2 to 87.0 mGy cm(2). The results showed that there exists a large difference between the patient exposures among different dental facilities. It was also observed that dentists working with faster film type or higher tube voltage are not always associated with lower exposure. The study demonstrated the necessity to have the DRLs laid out as guidelines in dental radiology.