Fabien Forest

Dysembryoplastic Neuroepithelial Tumors Share with Pleomorphic Xanthoastrocytomas and Gangliogliomas BRAFV600E Mutation and Expression

Pediatric cortical glioneuronal benign tumors mainly include gangliogliomas (GG) [differential diagnoses pilocytic astrocytomas (PA) and pleomorphic xanthoastrocytomas (PXA)] and dysembryoplastic neuroepithelial tumor (DNT). DNT include the specific form and the controversial non‐specific form that lack the specific glioneuronal element. Our aims were to search for BRAFV600E mutation and CD34 expression in DNT, PXA, GG and PA to correlate BRAFV600E mutation with BRAFV600E expression and to evaluate their diagnostic and prognostic values. Ninety‐six children were included. BRAFV600E mutation was studied by sequencing and immunohistochemistry; CD34 expression was analyzed by immunohistochemistry. BRAFV600E mutation was detected in PXA (60%), GG (38.7%), DNT (30%, including 3/11 specific and 3/9 non‐specific forms) and PA (12.5%). BRAFV600E expression was recorded in PXA (60%), GG (45.2%) and DNT (30%). CD34 expression was recorded in PXA (60%), GG (58.1%), DNT (25%) and PA (12.5%). Neither CD34 expression nor BRAFV600E status was predictive of prognosis, except for PA tumors where CD34 expression was associated with a shorter overall survival. In conclusion, DNT shared with PXA and GG, BRAFV600E mutation and/or CD34 expression, which represent molecular markers for these tumors, and we recommend searching for CD34 expression and BRAFV600E mutation in all DNT, especially the non‐specific forms.

Supratentorial clear cell ependymomas with branching capillaries demonstrate characteristic clinicopathological features and pathological activation of nuclear factor-kappaB signaling

BACKGROUND Clear cell ependymoma is one of the 4 main histological subtypes of ependymomas defined by the World Health Organization (WHO) classification of tumors of the CNS. DNA methylation profiling can distinguish 4 subgroups of intracranial ependymomas, including supratentorial (ST) ependymomas with Yes-associated protein 1 fusion (YAP1), ST ependymomas with fusion of v-rel avian reticuloendotheliosis viral oncogene homolog A (RELA), posterior fossa ependymomas with balanced genome, and posterior fossa ependymomas with chromosomal instability. In addition, trisomy 19 is a genomic hallmark of ependymomas with rich branching capillaries. However, the relation of histological and molecular subtypes is unclear. METHODS Here, we report a series of 20 ependymomas histologically defined by clear cells and branching capillaries. RESULTS We observed a strong male predominance. Median age at surgery was 10.4 years (range, 0.8-68.4). All cases were ST, cortical, contrast enhancing, and most often frontal, cystic, and calcified. All tumors qualified as WHO grade III. Some of them exhibited neuronal differentiation. Trisomy 19 was recorded in 13 cases. All samples strongly accumulated p65RelA protein within nuclei, indicating pathological activation of the nuclear factor-kappaB pathway. We identified causative C11ORF95-RELA fusion in almost all cases. Median progression-free survival and overall survival were 11.4 years (95% CI: 5.1-17.8) and not reached, respectively. CONCLUSION ST clear cell ependymomas with branching capillaries display characteristic clinicopathological features and are associated with pathological activation of nuclear factor-kappaB signaling, which may indicate a potential novel target for therapy in these patients.

Conventional chondrosarcoma in a survivor of rhabdoid tumor: enlarging the spectrum of tumors associated with SMARCB1 germline mutations.

SMARCB1 germline mutations mainly predispose to rhabdoid tumors. However, less aggressive tumors with a later onset have also been reported in a context of SMARCB1 constitutional mutation-that is, schwannomatosis and meningiomatosis. No other tumor type has formally been observed in such a context thus far. We report on a patient treated for a thoracic malignant rhabdoid tumor at 8 years of age who subsequently developed a mandibular conventional chondrosarcoma at 13 years of age. Both tumors showed a loss of BAF47 expression. The malignant rhabdoid tumor exhibited a large 22q11.2 deletion and an intragenic deletion of SMARCB1 (exons 1 to 3), thus leading to a biallelic inactivation. A 2.8 Mbp deletion encompassing SMARCB1 was found in the germline. This context was a strong incentive to investigate SMARCB1 alterations in the second tumor. As expected, the chondrosarcoma showed the large 22q11.2 deletion but also an additional c.243C>G(p.Tyr18X) premature stop codon in the remaining allele. This report relates for the first time a pediatric conventional chondrosarcoma to the wide family of SMARCB1-deficient tumors. Moreover, we report here the first case of conventional chondrosarcoma arising in a context of constitutional SMARCB1 deletion and, thus, enlarge the spectrum of this tumor predisposition syndrome.

Correlation between ERK1 and STAT3 expression and chemoresistance in patients with conventional osteosarcoma

BackgroundThe standard therapy regimen of conventional osteosarcoma includes neoadjuvant chemotherapy followed by surgical resection and postoperative chemotherapy. The percentage of necrotic tissue following induction chemotherapy is assessed by using the Huvos grading system, which classifies patients as “poor responders” (PR) and “good responders” (GR). The aim of this study was to identify molecular markers expressed differentially between good and poor responders to neoadjuvant chemotherapy in order to predict the response to chemotherapy in conventional osteosarcomas before beginning treatment.MethodsSuppression Substractive Hybridization (SSH) was performed by using cDNA from frozen biopsy specimens. Expression of selected relevant genes identified by SSH was validated by using QRT-PCR. Immunohistochemistry (IHC) on tissue microarray (TMA) sections of 52 biopsies was performed to investigate protein expression in an independent cohort.ResultsERK1 and STAT3 mRNA level were significantly different between PR and GR in an independent cohort. Phosphorylated STAT3 and ERK1 expressions by IHC on TMA were correlated with poor response to chemotherapy.ConclusionsOur results suggest that ERK1 and STAT3 expression are good predictive markers for chemotherapy response and that inhibitors might be used in combination with common chemotherapeutic drugs in conventional osteosarcomas.

ALDH1 is an immunohistochemical diagnostic marker for solitary fibrous tumours and haemangiopericytomas of the meninges emerging from gene profiling study

BackgroundSolitary Fibrous Tumours (SFT) and haemangiopericytomas (HPC) are rare meningeal tumours that have to be distinguished from meningiomas and more rarely from synovial sarcomas. We recently found that ALDH1A1 was overexpressed in SFT and HPC as compared to soft tissue sarcomas. Using whole-genome DNA microarrays, we defined the gene expression profiles of 16 SFT/HPC (9 HPC and 7 SFT). Expression profiles were compared to publicly available expression profiles of additional SFT or HPC, meningiomas and synovial sarcomas. We also performed an immunohistochemical (IHC) study with anti-ALDH1 and anti-CD34 antibodies on Tissue Micro-Arrays including 38 SFT (25 meningeal and 13 extrameningeal), 55 meningeal haemangiopericytomas (24 grade II, 31 grade III), 163 meningiomas (86 grade I, 62 grade II, 15 grade III) and 98 genetically confirmed synovial sarcomas.ResultsALDH1A1 gene was overexpressed in SFT/HPC, as compared to meningiomas and synovial sarcomas. These findings were confirmed at the protein level. 84% of the SFT and 85.4% of the HPC were positive with anti-ALDH1 antibody, while only 7.1% of synovial sarcomas and 1.2% of meningiomas showed consistent expression. Positivity was usually more diffuse in SFT/HPC compared to other tumours with more than 50% of tumour cells immunostained in 32% of SFT and 50.8% of HPC. ALDH1 was a sensitive and specific marker for the diagnosis of SFT (SE = 84%, SP = 98.8%) and HPC (SE = 84.5%, SP = 98.7%) of the meninges. In association with CD34, ALDH1 expression had a specificity and positive predictive value of 100%.ConclusionWe show that ALDH1, a stem cell marker, is an accurate diagnostic marker for SFT and HPC, which improves the diagnostic value of CD34. ALDH1 could also be a new therapeutic target for these tumours which are not sensitive to conventional chemotherapy.

Characteristics of H3 K27M-mutant gliomas in adults.

Background Diffuse H3 K27M-mutant gliomas occur primarily in children but can also be encountered in adults. The aim of this study was to describe the characteristics of H3 K27M-mutant gliomas in adults. Methods We analyzed the characteristics of 21 adult H3 K27M-mutant gliomas and compared them with those of 135 adult diffuse gliomas without histone H3 and without isocitrate dehydrogenase (IDH) mutation (IDH/H3 wild type). Results The median age at diagnosis in H3 K27M-mutant gliomas was 32 years (range: 18-82 y). All tumors had a midline location (spinal cord n = 6, thalamus n = 5, brainstem n = 5, cerebellum n = 3, hypothalamus n = 1, and pineal region n = 1) and were IDH and BRAF-V600E wild type. The identification of an H3 K27M mutation significantly impacted the diagnosis in 3 patients (14%) for whom the histological aspect initially suggested a diffuse low-grade glioma and in 7 patients (33%) for whom pathological analysis hesitated between a diffuse glioma, ganglioglioma, or pilocytic astrocytoma. Compared with IDH/H3 wild-type gliomas, H3 K27M-mutant gliomas were diagnosed at an earlier age (32 vs 64 y, P < .001), always had a midline location (21/21 vs 21/130, P < .001), less frequently had a methylated MGMT promoter (1/21 vs 52/129, P = .002), and lacked EGFR amplification (0/21 vs 26/128, P = .02). The median survival was 19.6 months in H3 K27M-mutant gliomas and 17 months in IDH/H3 wild-type gliomas (P = .3). Conclusion In adults, as in children, H3 K27M mutations define a distinct subgroup of IDH wild-type gliomas characterized by a constant midline location, low rate of MGMT promoter methylation, and poor prognosis.

Postmortem injuries inflicted by crawfish: Morphological and histological aspects

A scavenging postmortem crawfish (Austropotamobius pallipes) is presented. A 60-year-old woman was found dead immersed in 2m of water in an artificial lack near a dam. The divers, on discovering the body, observed numerous crawfish near the face, the abdomen and the hands of the cadaver that disappeared at their approach. Her face showed extensive hemorrhagic lesions of the eyelids, lips and neck, initially attributed by the police investigators to a possible criminal assault. On autopsy, the face injuries were identified as a postmortem defect by animal scavenging. We present the macro- and microscopic aspects of these postmortem changes in relation to animal predation.

3D map of the human corneal endothelial cell.

Corneal endothelial cells (CECs) are terminally differentiated cells, specialized in regulating corneal hydration and transparency. They are highly polarized flat cells that separate the cornea from the aqueous humor. Their apical surface, in contact with aqueous humor is hexagonal, whereas their basal surface is irregular. We characterized the structure of human CECs in 3D using confocal microscopy of immunostained whole corneas in which cells and their interrelationships remain intact. Hexagonality of the apical surface was maintained by the interaction between tight junctions and a submembraneous network of actomyosin, braced like a drum. Lateral membranes, which support enzymatic pumps, presented complex expansions resembling interdigitated foot processes at the basal surface. Using computer-aided design and drafting software, we obtained a first simplified 3D model of CECs. By comparing their expression with those in epithelial, stromal and trabecular corneal cells, we selected 9 structural or functional proteins for which 3D patterns were specific to CECs. This first 3D map aids our understanding of the morphologic and functional specificity of CECs and could be used as a reference for characterizing future cell therapy products destined to treat endothelial dysfunctions.

p16 and p53 expression status in head and neck squamous cell carcinoma: a correlation with histological, histoprognostic and clinical parameters

Different histopathology and prognosis characterise the human papillomavirus (HPV)-related oropharyngeal tumours, but squamous cell carcinomas (SCC) of other localisations have not been exhaustively studied. Tissues from 120 patients with a head and neck SCC were studied for the expression of p16 and p53, and the Brandwein-Gensler (BG) histological risk assessment model. p16 positivity and p53 normal expression were significantly correlated with non-smoking, an earlier T stage and a non-keratinising morphology. The BG risk score was not associated with p16 or p53 expression; p16 expression was associated with a lymphocytic T-cytotoxic response. BG risk score was significantly correlated with overall survival and progression-free survival, while neither p16 nor p53 expression were associated with prognosis. p16 and p53 expression are associated with the histological subtype and the T stage even in non-oropharyngeal-restricted tumours. The BG risk score is not correlated with p16 or p53 and retains its power in non-site-specific SCCs.

Comparison of endothelial cell density of organ cultured corneas with cornea donor study.

Purpose: Determination of the endothelial cell density (ECD) by eye banks is paramount in donor cornea qualification. Unbiased measurement avoids wastage and grafts with an increased risk of premature failure. Internal calibration of the counting method is essential, but external validation would add an extra stage in the assessment of reliability. In this respect, data published by the multicenter Cornea Donor Study (CDS) in 2005 is a reference. The aim of the study was to compare ECD determined within a single eye bank, which uses calibrated image analysis software designed for transmitted light microscopy images of organ cultured corneas, with the CDS data determined on specular microscopy images of corneas stored at 4°C. Methods: ECD of consecutive corneas retrieved between 2005 and 2013 was determined after exposure to 0.9% NaCl. More than 300 ECs were counted on 3 fields of the central 8 mm. Endothelial cell boundaries were automatically drawn and verified by a skilled technician who performed all necessary corrections. Results: Three thousand fifty-two corneas were analyzed, of which 48.5% donors were >75 years (CDS upper age limit). Between 10 and 75 years, the ECD varied according to donor age exactly in the same manner as in the CDS, but were consistently higher of 100 ± 25 cells per square millimeter (P < 0.001). Conclusions: ECD determined by a computer-aided method from transmitted light microscopy images compares favorably with the American CDS reference series. The slight systematic difference on either side of the Atlantic Ocean could be due to (1) differences in counting principles and/or (2) higher shrinkage of the cornea caused by stromal edema in organ culture.