Aims Previous estimates of the prevalence of mismatch repair (MMR) deficiency and Lynch syndrome in small bowel cancer have varied widely. The aim of this study was to establish the prevalence of... Show moreAims Previous estimates of the prevalence of mismatch repair (MMR) deficiency and Lynch syndrome in small bowel cancer have varied widely. The aim of this study was to establish the prevalence of MMR deficiency and Lynch syndrome in a large group of small bowel adenocarcinomas. Methods To this end, a total of 400 small bowel adenocarcinomas (332 resections, 68 biopsies) were collected through the Dutch nationwide registry of histopathology and cytopathology (Pathologisch-Anatomisch Landelijk Geautomatiseerd Archief (PALGA)). No preselection criteria, such as family history, were applied, thus avoiding (ascertainment) bias. MMR deficiency status was determined by immunohistochemical staining of MMR proteins, supplemented by MLH1 promoter hypermethylation analysis and next generation sequencing of the MMR genes. Results MMR deficiency was observed in 22.3% of resected and 4.4% of biopsied small bowel carcinomas. Prevalence of Lynch syndrome was 6.2% in resections and 0.0% in biopsy samples. Patients with Lynch syndrome-associated small bowel cancer were significantly younger at the time of diagnosis than patients with MMR-proficient and sporadic MMR-deficient cancers (mean age of 54.6 years vs 66.6 years and 68.8 years, respectively, p<0.000). Conclusions The prevalence of MMR deficiency and Lynch syndrome in resected small bowel adenocarcinomas is at least comparable to prevalence in colorectal cancers, a finding relevant both for treatment (immunotherapy) and family management. We recommend that all small bowel adenocarcinomas should be screened for MMR deficiency. Show less
For a nationwide real-word data study on the application of predictive mutation testing of patients with colorectal cancer (CRC) for anti-epidermal growth factor receptor (EGFR) therapy... Show moreFor a nationwide real-word data study on the application of predictive mutation testing of patients with colorectal cancer (CRC) for anti-epidermal growth factor receptor (EGFR) therapy stratification, pathology data were collected from the Dutch Pathology Registry from October 2017 until June 2019 (N=4060) and linked with the Netherlands Cancer Registry. Mutation testing rates increased from 24% at diagnosis of stage IV disease to 60% after 20-23 months of follow-up (p<0.001). Application of anti-EGFR therapy in KRAS/NRAS wild-type patients was mainly observed from the third treatment line onwards (65% vs 17% in first/second treatment line (p<0.001)). The national average KRAS/NRAS/BRAF mutation rate was 63.9%, being similar for next-generation sequencing (NGS)-based approaches and single gene tests (64.4% vs 61.2%, p=ns). NGS-based approaches detected more additional potential biomarkers, for example, ERBB2 amplifications (p<0.05). Therefore, single gene tests are suitable to stratify patients with mCRC for anti-EGFR therapy, but NGS is superior enabling upfront identification of therapy resistance or facilitate enrolment into clinical trials. Show less
Background The aim of this study was to investigate the possible causes of tumour latency in uveal melanoma primarily through the analysis of micrometastases in tissue obtained from donors... Show moreBackground The aim of this study was to investigate the possible causes of tumour latency in uveal melanoma primarily through the analysis of micrometastases in tissue obtained from donors postmortem. Various explanations have been proposed but there is no clear answer from animal studies and few human data. The main hypotheses may be divided into several areas-immunological control of metastatic cells, lack of angiogenesis within micrometastases and reduced cell turnover. Methods 196 patients were recruited to the study between 2003 and 2007. Patients were invited to take part and their relatives agreed to postmortem examination of their liver and lungs in the event of their death, including tissue sampling to assess the presence of micrometastases and their biology. Metastatic cells were detected by immunohistochemistry using a pan-melanoma antibody reagent, and by quantitative reverse transcriptase (qRT)-PCR for three melanoma-associated genes (tyrosinase Melan-A, and gp100) and a housekeeping gene (HMBS/PBGD) in samples stored in RNAlater or as formalin-fixed paraffin-embedded tissue. Results 22 deaths were investigated at autopsy as part of the study. Sixteen patients died with large deposits of metastatic melanoma, while six patients died of other causes. In addition, a liver resection for hepatic adenoma provided further tissue from a case without clinical evidence of metastasis. Metastatic melanoma cells were identified by immunohistochemistry of the liver samples in one case and by qRT-PCR in two further cases without macrometastases. There was no evidence of multicellular micrometastases sufficiently large to require angiogenesis and no associated inflammation was observed. Conclusion The most likely explanation for latency in this setting is the inability of uveal melanoma cells in metastatic sites to grow. Show less
Heyning, F.H.; Jansen, P.M.; Hogendoorn, P.C.W.; Szuhai, K. 2010
Aims Primary non-Hodgkin's lymphoma of bone (PLB) is a rare subtype of primary extranodal diffuse large B cell lymphoma. PLB has morphological homogeneity and a relatively favourable clinical... Show moreAims Primary non-Hodgkin's lymphoma of bone (PLB) is a rare subtype of primary extranodal diffuse large B cell lymphoma. PLB has morphological homogeneity and a relatively favourable clinical behaviour. Recent studies report that array-based comparative genomic hybridisation (array-CGH) analysis can be used to classify lymphomas into clinically and biologically relevant phenotypes and possibly reveal differences in oncogenic mechanisms. Here the authors performed the first array-CGH study to detect illness related genomic alterations in nine, clinically well-staged primary lymphoma of bone cases. Methods Nine frozen samples from primary lymphoma of bone patients were immunophenotyped and subsequently investigated using a well-established array-CGH platform. The array-CGH results were confirmed by fluorescence in situ hybridisation. Clinical data and follow-up were obtained for all nine patients. Results Of the nine patients, eight reached complete remission, and one had progressive disease and died of primary lymphoma of bone. Frequent aberrations were: loss of 14q32 (n=7), trisomy 7 (n=6), gain of the long arm of chromosome 1 (n=5) and amplification of 2p16.1 (n=4). No statistically significant correlation between genetic abnormalities and clinical outcome was found. Conclusions The authors found several recurrent genomic aberrations, including five cases with gain of 1q and four cases with 2p16.1 amplification. These findings are associated with a germinal centre-like phenotype and favourable treatment outcome, and differ from chromosomal aberrations found in other extranodal lymphomas. These findings further substantiate the notion that primary lymphoma of bone should be considered as a distinct entity not only on clinic-pathological grounds but also on the genomic level as well. Show less
