Publications by authors named "Bleeker F"

Germline SMAD4 pathogenic variants (PVs) cause juvenile polyposis syndrome (JPS), which is known for an increased risk of gastrointestinal juvenile polyps and gastrointestinal cancer. Many patients with SMAD4 PV also show signs of hereditary hemorrhagic telangiectasia (HHT) and some patients have aneurysms and dissections of the thoracic aorta. Here we describe two patients with a germline SMAD4 PV and a remarkable clinical presentation including multiple medium-sized arterial aneurysms.

View Article and Find Full Text PDF

Background: This study investigates the potential influence of genotype and parent-of-origin effects (POE) on the clinical manifestations of Lynch syndrome (LS) within families carrying (likely) disease-causing MSH6 germline variants.

Patients And Methods: A cohort of 1615 MSH6 variant carriers (310 LS families) was analyzed. Participants were categorized based on RNA expression and parental inheritance of the variant.

View Article and Find Full Text PDF

Diagnosis of Lynch syndrome (LS) caused by a pathogenic germline MSH6 variant may be complicated by discordant immunohistochemistry (IHC) and/or by a microsatellite stable (MSS) phenotype. This study aimed to identify the various causes of the discordant phenotypes of colorectal cancer (CRC) and endometrial cancer (EC) in MSH6-associated LS. Data were collected from Dutch family cancer clinics.

View Article and Find Full Text PDF

An inherited single nucleotide variant (SNV) in the 5'UTR of the BRCA1 gene c.-107A > T was identified to be related to BRCA1 promoter hypermethylation and a hereditary breast and ovarian cancer phenotype in two UK families. We investigated whether this BRCA1 variant was also present in a Dutch cohort of breast and ovarian cancer patients with tumor BRCA1 promoter hypermethylation.

View Article and Find Full Text PDF

Variants of the C19ORF12-gene have been described in patients with spastic paraplegia type 43 and in patients with mitochondrial membrane protein-associated neurodegeneration (MPAN), a subtype of neurodegeneration associated with brain iron accumulation (NBIA). In both subtypes optic atrophy and neuropathy have been frequently described. This case report describes a patient with bilateral optic atrophy and severe distal muscle weakness based on motor neuropathy without involvement of the central nervous system.

View Article and Find Full Text PDF

Recognizing a tumor predisposition syndrome (TPS) in a child with cancer is of clinical relevance. Earlier we developed a screening tool to increase diagnostic accuracy and clinical efficiency of identifying TPSs in children with cancer. Here we report on the value of this tool in clinical practice.

View Article and Find Full Text PDF

Germline pathogenic variants in the BRCA1-associated protein-1 () gene cause the BAP1-tumor predisposition syndrome (BAP1-TPDS, OMIM 614327). BAP1-TPDS is associated with an increased risk of developing uveal melanoma (UM), cutaneous melanoma (CM), malignant mesothelioma (MMe), renal cell carcinoma (RCC), meningioma, cholangiocarcinoma, multiple non-melanoma skin cancers, and -inactivated nevi. Because of this increased risk, it is important to identify patients with BAP1-TPDS.

View Article and Find Full Text PDF

Background: Lynch syndrome (LS) is caused by germline mismatch repair (MMR) gene mutations. De novo MMR gene mutations are rare, and somatic mosaicism in LS is thought to be infrequent. We describe the first case of somatic mosaicism by a de novo MLH1 mutation for a patient diagnosed with a rectosigmoid adenocarcinoma at age 31.

View Article and Find Full Text PDF

Individuals at high risk for Lynch syndrome (LS) should be offered genetic counselling, since preventive options are available. However, uptake of genetic services and follow-up care are currently suboptimal, possibly caused by inadequate exchange of information. Therefore, this qualitative study aims to gain insight in the process of information exchange between patients diagnosed with LS and their non-genetic (i.

View Article and Find Full Text PDF

Somatic mutations in occur in approximately 20% of patients with myeloid neoplasms, including acute myeloid leukemia (AML). IDH1/2 enzymes produce -2-hydroxyglutarate (2HG), which associates with increased DNA damage and improved responses to chemo/radiotherapy and PARP inhibitors in solid tumor cells. Whether this also holds true for AML is not known.

View Article and Find Full Text PDF

Introduction: Recognising a tumour predisposition syndrome (TPS) in childhood cancer patients is of major clinical relevance. The presence of a TPS may be suggested by the type of tumour in the child. We present an overview of 23 childhood tumours that in themselves should be a reason to refer a child for genetic consultation.

View Article and Find Full Text PDF

Introduction: Recognising a tumour predisposition syndrome (TPS) in patients with childhood cancer is of significant clinical relevance, as it affects treatment, prognosis and facilitates genetic counselling. Previous studies revealed that only half of the known TPSs are recognised during standard paediatric cancer care. In current medical practice it is impossible to refer every patient with childhood cancer to a clinical geneticist, due to limited capacity for routine genetic consultation.

View Article and Find Full Text PDF

The economic situation in German Hospitals is tense and needs the implementation of differentiated controlling instruments. Accordingly, parameters of revenue development of different organizational units within a hospital are needed. This is particularly necessary in the revenue and cost-intensive operating theater field.

View Article and Find Full Text PDF

In schwannomatosis, germline SMARCB1 or LZTR1 mutations predispose to the development of multiple benign schwannomas. Besides these, other tumors may occur in schwannomatosis patients. We present a 45-year-old male patient who developed multiple schwannomas and in addition a malignant type 1 papillary renal cell carcinoma (pRCC1).

View Article and Find Full Text PDF

Isocitrate dehydrogenase 1 (IDH1) is mutated in various types of human cancer to IDH1(R132H), a structural alteration that leads to catalysis of α-ketoglutarate to the oncometabolite D-2-hydroxyglutarate. In this study, we present evidence that small-molecule inhibitors of IDH1(R132H) that are being developed for cancer therapy may pose risks with coadministration of radiotherapy. Cancer cells heterozygous for the IDH1(R132H) mutation exhibited less IDH-mediated production of NADPH, such that after exposure to ionizing radiation (IR), there were higher levels of reactive oxygen species, DNA double-strand breaks, and cell death compared with IDH1 wild-type cells.

View Article and Find Full Text PDF

Background: Improvement of quality of care and patient safety while decreasing costs are major challenges in healthcare systems. This challenge includes the avoidance of perioperative hypothermia to reduce the associated adverse effects, length of stay and treatment costs. Due to the medical and economic relevance the national S3 guidelines for the prevention of perioperative hypothermia were recently published.

View Article and Find Full Text PDF

Background: O(6)-methyl-guanine-methyl-transferase (MGMT) silencing by promoter methylation may identify cancer patients responding to the alkylating agents dacarbazine or temozolomide.

Patients And Methods: We evaluated the prognostic and predictive value of MGMT methylation testing both in tumor and cell-free circulating DNA (cfDNA) from plasma samples using an ultra-sensitive two-step digital PCR technique (methyl-BEAMing). Results were compared with two established techniques, methylation-specific PCR (MSP) and Bs-pyrosequencing.

View Article and Find Full Text PDF

Mutations in isocitrate dehydrogenase 1/2 (IDH1/2(MT)) are drivers of a variety of myeloid neoplasms. As they yield the same oncometabolite, D-2-hydroxyglutarate, they are often treated as equivalent, and pooled. We studied the validity of this approach and found IDH1/2 mutations in 179 of 2119 myeloid neoplasms (8%).

View Article and Find Full Text PDF

Background: Glioblastoma is a highly malignant brain tumor for which no cure is available. To identify new therapeutic targets, we performed a mutation analysis of kinase genes in glioblastoma.

Methods: Database mining and a literature search identified 76 kinases that have been found to be mutated at least twice in multiple cancer types before.

View Article and Find Full Text PDF

Mutations in isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) are key events in the development of glioma, acute myeloid leukemia (AML), chondrosarcoma, intrahepatic cholangiocarcinoma (ICC), and angioimmunoblastic T-cell lymphoma. They also cause D-2-hydroxyglutaric aciduria and Ollier and Maffucci syndromes. IDH1/2 mutations are associated with prolonged survival in glioma and in ICC, but not in AML.

View Article and Find Full Text PDF

In many malformation syndromes benign and malignant tumours develop more frequently than in the general population. Malformations result from an abnormal intrinsic developmental process. It can be hypothesised that disturbed regulation of cell growth as can become evident by the presence of benign and malignant tumours, which will occur at the same site of a malformation or at other sites at which the gene involved in the malformation is functioning.

View Article and Find Full Text PDF