48 research outputs found

    Minimally invasive classification of pediatric solid tumors using reduced representation bisulfite sequencing of cell-free DNA : a proof-of-principle study

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    In the clinical management of pediatric solid tumors, histological examination of tumor tissue obtained by a biopsy remains the gold standard to establish a conclusive pathological diagnosis. The DNA methylation pattern of a tumor is known to correlate with the histopathological diagnosis across cancer types and is showing promise in the diagnostic workup of tumor samples. This methylation pattern can be detected in the cell-free DNA. Here, we provide proof-of-concept of histopathologic classification of pediatric tumors using cell-free reduced representation bisulfite sequencing (cf-RRBS) from retrospectively collected plasma and cerebrospinal fluid samples. We determined the correct tumor type in 49 out of 60 (81.6%) samples starting from minute amounts (less than 10 ng) of cell-free DNA. We demonstrate that the majority of misclassifications were associated with sample quality and not with the extent of disease. Our approach has the potential to help tackle some of the remaining diagnostic challenges in pediatric oncology in a cost-effective and minimally invasive manner. Translational relevance: Obtaining a correct diagnosis in pediatric oncology can be challenging in some tumor types, especially in renal tumors or central nervous system tumors. Furthermore, the diagnostic odyssey can result in anxiety and discomfort for these children. By applying a novel technique, reduced representation bisulfite sequencing on cell-free DNA (cf-RRBS), we show the feasibility of obtaining the histopathological diagnosis with a minimally invasive test on either plasma or cerebrospinal fluid. Furthermore, we were able to derive the copy number profile or tumor subtype from the same assay. Given that primary tumor material might be difficult to obtain, in particular in critically ill children or depending on the tumor location, and might be limited in terms of quantity or quality, our assay could become complementary to the classical tissue biopsy in difficult cases

    Cell-Free DNA as a Diagnostic and Prognostic Biomarker in Pediatric Rhabdomyosarcoma

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    PURPOSE: Total cell-free DNA (cfDNA) and tumor-derived cfDNA (ctDNA) can be used to study tumor-derived genetic aberrations. We analyzed the diagnostic and prognostic potential of cfDNA and ctDNA, obtained from pediatric patients with rhabdomyosarcoma. METHODS: cfDNA was isolated from diagnostic plasma samples from 57 patients enrolled in the EpSSG RMS2005 study. To study the diagnostic potential, shallow whole genome sequencing (shWGS) and cell-free reduced representation bisulphite sequencing (cfRRBS) were performed in a subset of samples and all samples were tested using droplet digital polymerase chain reaction to detect methylated RASSF1A ( RASSF1A-M). Correlation with outcome was studied by combining cfDNA RASSF1A-M detection with analysis of our rhabdomyosarcoma-specific RNA panel in paired cellular blood and bone marrow fractions and survival analysis in 56 patients. RESULTS: At diagnosis, ctDNA was detected in 16 of 30 and 24 of 26 patients using shallow whole genome sequencing and cfRRBS, respectively. Furthermore, 21 of 25 samples were correctly classified as embryonal by cfRRBS. RASSF1A-M was detected in 21 of 57 patients. The presence of RASSF1A-M was significantly correlated with poor outcome (the 5-year event-free survival [EFS] rate was 46.2% for 21 RASSF1A-M ‒positive patients, compared with 84.9% for 36 RASSF1A-M ‒negative patients [ P < .001]). RASSF1A-M positivity had the highest prognostic effect among patients with metastatic disease. Patients both negative for RASSF1A-M and the rhabdomyosarcoma-specific RNA panel (28 of 56 patients) had excellent outcome (5-year EFS 92.9%), while double-positive patients (11/56) had poor outcome (5-year EFS 13.6%, P < .001). CONCLUSION: Analyzing ctDNA at diagnosis using various techniques is feasible in pediatric rhabdomyosarcoma and has potential for clinical use. Measuring RASSF1A-M in plasma at initial diagnosis correlated significantly with outcome, particularly when combined with paired analysis of blood and bone marrow using a rhabdomyosarcoma-specific RNA panel

    Case report : A suspicion of cortico-cerebral necrosis in a Belgian Blue herd after ingestion of moulded silage

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    After ingestion of moulded beet pulp silage, cases of cortico-cerebral necrosis (CCN) and mortalities have been observed in a Belgian Blue (BB) herd. Contamination with Paecilomyces spp., a mould that produces byssochlamic acid, malformins and patulin, has been proven. Among these toxins, patulin is known to have cancerogenic, immunosuppressive and tremorgenic effects, but also acts on the respiratory and digestive systems. Twenty-five days after progressive introduction of beet pulp silage into the ration of a dual purpose BB herd, most of the animals showed diminished appetite, salivation and decreased milk production. All 35 cows were reluctant to consume the beet pulp silage, but continued to eat grass silage voluntarily. Seven of them showed anorexia and nervous symptoms, like head pressing and blindness. Four animals died within 1 week after onset of neurological symptoms. No necropsy has been performed, since legislation does not allow post-mortem examination of the central nervous system in the field. The three survivors had been treated successfully with thiamine (10 mg/kg, IV, TID) and recovered completely within five days. After the beet pulp silage had been identified as causative agent, it had been removed from the animals’ ration and no more clinical case has been observed. Four weeks later, the same beet pulp silage has been reintroduced into the animals’ ration and provoked again diminished appetite, salivation and a decrease in milk production in most of the animals. Clinical signs were also suggesting lead poisoning but any contact with lead containing material could have been excluded. Silage was obviously moulded and analysis revealed the presence of 1.6 million CFU Paecilomyces spp./g of silage. Although no further investigation has been made to identify the mycotoxins, an intoxication with patulin has been suspected, since other mycotoxins produced by these species are less toxic. Although it has not been described that CCN can be induced by ingestion of Paecilomyces spp., it seems that there is a close relation between ingestion of Paecilomyces-contaminated silage and observed clinical signs in this herd

    Signes de neurotoxicité dans un troupeau Blanc Bleu Belge après ingestion d'ensilage moisi

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    peer reviewedAfter ingestion of moulded beet pulp silage, cases of cerebro-cortical necrosis (CCN) and mortalities were observed in a dual purpose Belgian Blue (BB) herd. Contamination with Paecilomyces spp., a mould that produces byssochlamic acid, malformins and patulin, was proven. Twenty-five days after progressive introduction of beet pulp silage into the ration, most of the animals showed diminished appetite, excessive salivation and decreased milk production. Some of them showed anorexia, head pressing and blindness while 4 animals died within 1 week after onset of neurological symptoms. The survivors had been treated successfully with thiamine and recovered completely within five days. Once the beet pulp silage had been identified as causative agent, it was removed from the animals’ ration and no more clinical cases were observed. Silage was obviously moulded and analysis revealed the presence of 1.6 million CFU Paecilomyces spp./g of silage. Although no further investigation was undertaken to identify the mycotoxins, intoxication with patulin was suspected, since other mycotoxins produced by these species are less toxic. Although it has not been described that CCN can be induced by ingestion of Paecilomyces spp., it seems that there is a close relation between ingestion of Paecilomyces-contaminated silage and clinical signs observed in this herd
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