Background Langerhans cell histiocytosis (LCH) is a rare haematological neoplasm characterized by the accumulation of CD1a(+), CD207/Langerin(+) histiocytes within inflammatory lesions. LCH can... Show moreBackground Langerhans cell histiocytosis (LCH) is a rare haematological neoplasm characterized by the accumulation of CD1a(+), CD207/Langerin(+) histiocytes within inflammatory lesions. LCH can involve any organ, but osteolytic bone lesions are most often encountered. Unifocal bone lesions may regress spontaneously after a thick needle biopsy has been taken. Case presentation In this case report, we describe the initial presentation of a single BRAF(V600E) mutated osteolytic LCH lesion in the left proximal humerus of a 46-year-old previously healthy woman. Despite multiple surgical interventions, she unexpectedly experienced progressive disease manifestation with significant soft tissue extension to the surrounding musculature, subcutis and epidermis. Because the disease manifestation remained loco-regional, radiotherapy (RT) (total dose of 20 Gy in 10 fractions) was initiated. Conclusion The patient achieved a complete remission without any side effects. This case highlights that RT is a rational and relative mild local treatment option for patients with aggressive LCH affecting the bone and surrounding soft tissue. Show less
Breeschoten, J. van; Wouters, M.W.J.M.; Wreede, L.C. de; Hilarius, D.H.; Haanen, J.B.; Blank, C.U.; ... ; Eertwegh, A.J.M. van den 2021
Objective: The aim of this study was to evaluate treatment patterns and overall survival (OS) of patients with BRAF(V600) wild-type and BRAF(V600)-mutant advanced melanoma in the Netherlands.... Show moreObjective: The aim of this study was to evaluate treatment patterns and overall survival (OS) of patients with BRAF(V600) wild-type and BRAF(V600)-mutant advanced melanoma in the Netherlands. Methods: We selected patients of 18 years and over, diagnosed between 2016 and 2017 with unresectable stage IIIC or IV melanoma, registered in the Dutch Melanoma Treatment Registry. To assess the association of BRAF(V600)-mutation status with OS we used the Cox proportional-hazards model. Results: A total of 642 BRAF(V600) wild-type and 853 mutant patients were included in the analysis. Median OS did not differ significantly between both groups, 15.2 months (95% confidence interval [CI]: 13.2-19.2) versus 20.6 months (95% CI: 18.3-25.0). Survival rates at 6 and 12 months were significantly lower for BRAF(V600) wild-type patients compared with BRAF(V600)-mutant patients, 72.0% (95% CI: 68.6-75.6) and 56.0% (95% CI: 52.2-60.0) versus 83.4% (95% CI: 80.9-85.9) and 65.7% (95% CI: 62.6-69.0). Two-year survival was not significantly different between both groups, 41.1% (95% CI: 37.2-45.3) versus 47.0% (95% CI: 43.6-60.6). Between 0 and 10 months, BRAF(V600) wild-type patients had a decreased survival with a hazard ratio for OS of 2.00 (95% CI: 1.62-2.46) but this effect disappeared after 10 months. At 12 months, BRAF(V600)-mutant patients had started with second-line systemic treatment more often compared with BRAF(V600) wild-type patients (50% vs. 19%). Conclusion: These results suggest that advanced BRAF(V600) wild-type melanoma patients have worse survival than BRAF(V600)-mutated patients during the first 10 months after diagnosis because of less available treatment options. Show less
Langerhans Cell Histiocytosis (LCH) is a neoplastic disorder of hematopoietic origin characterized by inflammatory lesions containing clonal histiocytes (LCH-cells) intermixed with various immune... Show moreLangerhans Cell Histiocytosis (LCH) is a neoplastic disorder of hematopoietic origin characterized by inflammatory lesions containing clonal histiocytes (LCH-cells) intermixed with various immune cells, including T cells. In 50-60% of LCH-patients, the somatic BRAF(V600E) driver mutation, which is common in many cancers, is detected in these LCH-cells in an otherwise quiet genomic landscape. Non-synonymous mutations like BRAF(V600E) can be a source of neoantigens capable of eliciting effective antitumor CD8(+) T cell responses. This requires neopeptides to be stably presented by Human Leukocyte Antigen (HLA) class I molecules and sufficient numbers of CD8(+) T cells at tumor sites. Here, we demonstrate substantial heterogeneity in CD8(+) T cell density in n = 101 LCH-lesions, with BRAF(V600E) mutated lesions displaying significantly lower CD8(+) T cell:CD1a(+) LCH-cell ratios (p = 0.01) than BRAF wildtype lesions. Because LCH-lesional CD8(+) T cell density had no significant impact on event-free survival, we investigated whether the intracellularly expressed BRAF(V600E) protein is degraded into neopeptides that are naturally processed and presented by cell surface HLA class I molecules. Epitope prediction tools revealed a single HLA class I binding BRAF(V600E) derived neopeptide (KIGDFGLATEK), which indeed displayed strong to intermediate binding capacity to HLA-A*03:01 and HLA-A*11:01 in an in vitro peptide-HLA binding assay. Mass spectrometry-based targeted peptidomics was used to investigate the presence of this neopeptide in HLA class I presented peptides isolated from several BRAF(V600E) expressing cell lines with various HLA genotypes. While the HLA-A*02:01 binding BRAF wildtype peptide KIGDFGLATV was traced in peptides isolated from all five cell lines expressing this HLA subtype, KIGDFGLATEK was not detected in the HLA class I peptidomes of two distinct BRAF(V600E) transduced cell lines with confirmed expression of HLA-A*03:01 or HLA-A*11:01. These data indicate that the in silico predicted HLA class I binding and proteasome-generated neopeptides derived from the BRAF(V600E) protein are not presented by HLA class I molecules. Given that the BRAF(V600E) mutation is highly prevalent in chemotherapy refractory LCH-patients who may qualify for immunotherapy, this study therefore questions the efficacy of immune checkpoint inhibitor therapy in LCH. Show less
This thesis identifies specific targets, illustrates the role of these targets, and explores personalized therapeutic possibilities to inhibit tumor growth by using new treatment strategies.... Show moreThis thesis identifies specific targets, illustrates the role of these targets, and explores personalized therapeutic possibilities to inhibit tumor growth by using new treatment strategies. And the thesis describes a new animal model for CM. A proper model can mimic the human disorder and provide opportunities for studying tumor biology, and for seeking novel effective therapies to inhibit the dissemination of malignant cells. Subsequently, the potential role of immune checkpoint molecules and the presence of HLA class I antigens are studied. New animal models and therapeutic targets will broaden our understanding of CM, and help us to develop better treatments for primary and metastatic CM, thus prolonging patients’ survival. Show less
This thesis describes the research that investigated molecular biomarkers in defined groups of primary colorectal tumours to determine markers for site specific metastases.
Vries, M. de; Briaire-de Bruijn, I.; Cleton-Jansen, A.M.; Malessy, M.J.A.; Mey, A.G.L. van der; Hogendoorn, P.C.W. 2013
The first study described the colon tumor-specific methylation of a low CG-dense CpG island that is located in the first intron of the PTPRG gene (PTPRGint1). High levels of specificity and... Show moreThe first study described the colon tumor-specific methylation of a low CG-dense CpG island that is located in the first intron of the PTPRG gene (PTPRGint1). High levels of specificity and sensitivity of this region were observed in sporadic and familial colon cancer which makes this region interesting for application in epigenetic screening panels. In the second study the relation between mutations and DNA methylation was investigated in an attempt to identify initiating factors for DNA methylation in colon cancer. In this study, we were unable to identify an intrinsic tendency towards CpG island hypermethylation other than aberrant accumulation of CpG island methylation via a somatic mutation of BRAF. The relationship between BRAF mutations and DNA methylation was explored further in Chapter 4, which describes an improved study of DNA methylation in BRAF mutationassociated colon cancer. We describe BRAF mutation-specific promoter methylation of the FOX transcription factor genes FOXB1, FOXB2 and FOXD3 and speculate that this methylation might help these tumors escape BRAF-induced senescence. In the final study the DMH technique was combined with oligonucleotide microarrays that contained high CpG island coverage to determine the methylation patterns of infant B-ALL patients. The majority of MLL-rearranged infant ALL cases (i.e., those who are characterized by a t(4;11) or t(11;19) translocation) represent hypermethylated leukemias. In contrast, infant ALL patients with a t(9;11) translocation and those without any MLL translocation (wild-type MLL) displayed DNA methylation patterns that closely resembled the pattern seen in normal bone marrow. This study indicates that patients with a t(4;11) or t(11;19) translocation who have high levels of DNA methylation might be promising candidates for therapies that inhibit DNA methylation. Show less
