MYC and TP53 Alterations but Not MAPK Pathway Mutations Are Common Oncogenic Mechanisms in Follicular Dendritic Cell Sarcomas.

CONTEXT.­: Despite their stromal origin, follicular dendritic cells (FDCs) share many functions with hematopoietic system cells. FDC neoplasms are currently classified by the World Health Organization along with those of a histiocytic nature. However, the molecular alterations driving oncogenesis in FDC sarcomas (FDCSs) are beginning to be unveiled and do not seem to concur with those described in histiocytic neoplasms, namely MAPK pathway activation. OBJECTIVE.­: To identify molecular alterations driving tumorigenesis in FDCS. DESIGN.­: We investigated the role of MYC and TP53 in FDC-derived tumor oncogenesis and assessed comprehensively the status of the MAPK pathway in 16 FDCSs, 6 inflammatory pseudotumor (IPT)-like FDCSs, and 8 IPTs. RESULTS.­: MYC structural alterations (both amplifications and rearrangements) were identified in 5 of 14 FDCSs (35.7%), all associated with MYC overexpression. TP53 mutations were identified in 4 of 14 FDCSs (28.6%), all of which displayed intense and diffuse p53 expression. None of these alterations were identified in any IPT-like FDCSs or in IPT cases. No MAPK pathway gene alterations were identified in any of the cases studied. CONCLUSIONS.­: The presence of MYC and TP53 alterations and the lack of association with Epstein-Barr virus segregate classical FDCS from IPT-like FDCS, pointing at different oncogenic mechanisms in both entities. Our results suggest a possible oncogenic role of MYC and TP53 alterations in FDCS. The absence of MAPK pathway alterations confirms the lack of a significant role of this pathway in the oncogenesis of FDC-derived neoplasms.

Distinct molecular profile of IRF4-rearranged large B-cell lymphoma.

Pediatric large B-cell lymphomas (LBCLs) share morphological and phenotypic features with adult types but have better prognosis. The higher frequency of some subtypes such as LBCL with IRF4 rearrangement (LBCL-IRF4) in children suggests that some age-related biological differences may exist. To characterize the genetic and molecular heterogeneity of these tumors, we studied 31 diffuse LBCLs (DLBCLs), not otherwise specified (NOS); 20 LBCL-IRF4 cases; and 12 cases of high-grade B-cell lymphoma (HGBCL), NOS in patients ≤25 years using an integrated approach, including targeted gene sequencing, copy-number arrays, and gene expression profiling. Each subgroup displayed different molecular profiles. LBCL-IRF4 had frequent mutations in IRF4 and NF-κB pathway genes (CARD11, CD79B, and MYD88), losses of 17p13 and gains of chromosome 7, 11q12.3-q25, whereas DLBCL, NOS was predominantly of germinal center B-cell (GCB) subtype and carried gene mutations similar to the adult counterpart (eg, SOCS1 and KMT2D), gains of 2p16/REL, and losses of 19p13/CD70. A subset of HGBCL, NOS displayed recurrent alterations of Burkitt lymphoma-related genes such as MYC, ID3, and DDX3X and homozygous deletions of 9p21/CDKN2A, whereas other cases were genetically closer to GCB DLBCL. Factors related to unfavorable outcome were age >18 years; activated B-cell (ABC) DLBCL profile, HGBCL, NOS, high genetic complexity, 1q21-q44 gains, 2p16/REL gains/amplifications, 19p13/CD70 homozygous deletions, and TP53 and MYC mutations. In conclusion, these findings further unravel the molecular heterogeneity of pediatric and young adult LBCL, improve the classification of this group of tumors, and provide new parameters for risk stratification.

Burkitt-like lymphoma with 11q aberration: a germinal center-derived lymphoma genetically unrelated to Burkitt lymphoma.

Burkitt-like lymphoma with 11q aberration is characterized by pathological features and gene expression profile resembling those of Burkitt lymphoma but lacks the MYC rearrangement and carries an 11q-arm aberration with proximal gains and telomeric losses. Whether this lymphoma is a distinct category or a particular variant of other recognized entities is controversial. To improve the understanding of Burkitt-like lymphoma with 11q aberration we performed an analysis of copy number alterations and targeted sequencing of a large panel of B-cell lymphoma-related genes in 11 cases. Most patients had localized nodal disease and a favorable outcome after therapy. Histologically, they were high grade B-cell lymphoma, not otherwise specified (8 cases), diffuse large B-cell lymphoma (2 cases) and only one was considered as atypical Burkitt lymphoma. All cases had a germinal center B-cell signature and phenotype with frequent LMO2 expression. The patients with Burkitt-like lymphoma with 11q aberration had frequent gains of 12q12-q21.1 and losses of 6q12.1-q21, and lacked common Burkitt lymphoma or diffuse large B-cell lymphoma alterations. Potential driver mutations were found in 27 genes, particularly involving BTG2, DDX3X, ETS1, EP300, and GNA13 However, ID3, TCF3, or CCND3 mutations were absent in all cases. These results suggest that Burkitt-like lymphoma with 11q aberration is a germinal center-derived lymphoma closer to high-grade B-cell lymphoma or diffuse large B-cell lymphoma than to Burkitt lymphoma.

Human papillomavirus in laryngeal and hypopharyngeal lymphoepithelial carcinoma.

The involvement of human papillomavirus (HPV) in laryngeal and hypopharyngeal lymphoepithelial carcinoma was investigated in a series of ten cases (seven laryngeal and three hypopharyngeal), retrieved from the files of three tertiary hospitals in the 2000-2017 period, through polymerase chain reaction with SPF10 primers and INNO-LiPA HPV Genotyping Extra II (Innogenetics). Epstein-Barr virus (EBV) was tested in all cases with in situ hybridization INFORM EBER Probe (Ventana Medical Systems). p16 and p53 expression were immunohistochemically analyzed. Calculated annual incidence was 0.013/100,000, and prevalence was 0.2% of laryngeal and hypopharyngeal carcinomas. All cases were EBV negative. HPV was detected in five cases, three of which also overexpressed p16. HPV16 was detected in four cases, and HPV58 in one case. Five cases were HPV negative, only one of these five overexpressed p16. No recurrence was observed in nine cases during follow-up. The 5-year disease-specific-survival rate was 100%. Mean overall survival was 87 months. Lymphoepithelial carcinoma of the larynx and hypopharynx are not related to EBV. Simultaneous HPV+/p16+ is consistent with HPV causation in a fraction of laryngeal and hypopharyngeal lymphoepithelial carcinomas.

Lymphomatosis cerebri mimicking iatrogenic Creutzfeldt-Jakob disease.

Lymphomatosis cerebri (LC) is a rare variant of primary central nervous system lymphoma (PCNSL) whereby individual lymphoma cells infiltrate the cerebral white matter without causing a mass effect. The disease characteristically presents as a rapidly progressive dementia, which opens an ample differential diagnosis of toxic, metabolic, neurodegenerative and infective causes. Other presentations also include changes in personality, myoclonus and psychotic symptoms. Here we report a patient who presented with a rapidly progressive dementia with a unique surgical history of a dural mater graft in the 1970s. The diagnosis of iatrogenic Creutzfeldt-Jakob disease (iCJD) was initially considered. However, the patient's clinical status deteriorated rapidly with no response to symptomatic treatment and she died 2 months after symptom onset. A diagnosis of T-type LC was reached at autopsy.

Expression of MALT1 oncogene in hematopoietic stem/progenitor cells recapitulates the pathogenesis of human lymphoma in mice.

Chromosomal translocations involving the MALT1 gene are hallmarks of mucosa-associated lymphoid tissue (MALT) lymphoma. To date, targeting these translocations to mouse B cells has failed to reproduce human disease. Here, we induced MALT1 expression in mouse Sca1(+)Lin(-) hematopoietic stem/progenitor cells, which showed NF-κB activation and early lymphoid priming, being selectively skewed toward B-cell differentiation. These cells accumulated in extranodal tissues and gave rise to clonal tumors recapitulating the principal clinical, biological, and molecular genetic features of MALT lymphoma. Deletion of p53 gene accelerated tumor onset and induced transformation of MALT lymphoma to activated B-cell diffuse large-cell lymphoma (ABC-DLBCL). Treatment of MALT1-induced lymphomas with a specific inhibitor of MALT1 proteolytic activity decreased cell viability, indicating that endogenous Malt1 signaling was required for tumor cell survival. Our study shows that human-like lymphomas can be modeled in mice by targeting MALT1 expression to hematopoietic stem/progenitor cells, demonstrating the oncogenic role of MALT1 in lymphomagenesis. Furthermore, this work establishes a molecular link between MALT lymphoma and ABC-DLBCL, and provides mouse models to test MALT1 inhibitors. Finally, our results suggest that hematopoietic stem/progenitor cells may be involved in the pathogenesis of human mature B-cell lymphomas.

Differential hypermethylation of genes in vulvar cancer and lichen sclerosus coexisting or not with vulvar cancer.

Squamous cell carcinoma (SCC) of the vulva is a heterogeneous disease, associated or not with vulvar lichen sclerosus (LS). The precursor role of LS in vulvar cancer is unclear. We studied the epigenetic alterations of RASSF1A, RASSF2A, p16, TSP-1 and MGMT genes in vulvar SCCs, LS associated with SCC, isolated LS and normal vulvar skin. Gene hypermethylation and human papillomavirus presence were evaluated by methylation-specific PCR and PCR/reverse line blot, respectively. High-risk human papillomavirus types were present in 16.7% of the patients with vulvar SCC. There were increasing percentages of hypermethylation of genes from isolated LS to LS associated with vulvar SCC and vulvar SCC. The genes were hypermethylated more frequently in vulvar SCC associated with LS than in those not associated with LS, MGMT and RASSF2A being unmethylated in LS not associated with vulvar SCC. TSP-1 hypermethylation was related to recurrence in patients with vulvar cancer. Conclusions are as follows: (i) the epigenetic inactivation of genes is a common event in vulvar SCC and is also present in adjacent lesions, implying a possible precursor role for these alterations; (ii) MGMT and RASSF2A hypermethylation are present exclusively in vulvar SCC and LS associated with SCC, and absent from isolated LS; and (iii) TSP-1 hypermethylation is a bad prognosis factor in vulvar SCC.

Expanding the clinical, pathological and MRI phenotype of DNM2-related centronuclear myopathy.

Mutations in dynamin-2 (DNM2) cause autosomal dominant centronuclear myopathy (CNM). We report a series of 12 patients from eight families with CNM in whom we have identified a number of novel features that expand the reported clinicopathological phenotype. We identified two novel and five recurrent missense mutations in DNM2. Early clues to the diagnosis include relative weakness of neck flexors, external ophthalmoplegia and ptosis, although these are not present in all patients. Pes cavus was present in two patients, and in another two members of one family there was mild slowing of nerve conduction velocities. Whole-body MRI examination in two children and one adult revealed a similar pattern of involvement of selective muscles in head (lateral pterygoids), neck (extensors), trunk (paraspinal) and upper limbs (deep muscles of forearm). Findings in lower limbs and pelvic region were similar to that previously reported in adults with DNM2 mutations. Two patients presented with dystrophic changes as the predominant pathological feature on muscle biopsies; one of whom had a moderately raised creatine kinase, and both patients were initially diagnosed as congenital muscular dystrophy. DNM2 mutation analysis should be considered in patients with a suggestive clinical phenotype despite atypical histopathology, and MRI findings can be used to guide genetic testing. Subtle neuropathic features in some patients suggest an overlap with the DNM2 neuropathy phenotype. Missense mutations in the C-terminal region of the PH domain appear to be associated with a more severe clinical phenotype evident from infancy.

Hypermethylation of the thrombospondin-1 gene is associated with poor prognosis in penile squamous cell carcinoma.

OBJECTIVE: To evaluate the presence of human papillomavirus (HPV) infection, the methylation status in the promoter region of thrombospondin-1 (TSP-1), RAS association domain family 1A (RASSF1-A) and p16 genes, and the expression of TSP-1, CD31, p16 and p53 proteins in patients diagnosed with penile cancer, and the possible associations between these variables and clinical and pathological features. PATIENTS AND METHODS: HPV types, gene promoter hypermethylation and protein expression were analysed by reverse line blot, methylation-specific polymerase chain reaction, and immunohistochemistry, respectively, in 24 penile squamous cell carcinomas. RESULTS: HPV infection was detected in 11 of 24 cases (46%), and TSP-1, RASSF1-A and p16 genes were hypermethylated in 46%, 42% and 38% of the tumours, respectively. TSP-1 hypermethylation was associated with unfavourable histological grade (grade 3; P = 0.033), vascular invasion (P = 0.023), weak expression of TSP-1 protein (P = 0.041), and shorter overall survival (P = 0.04). TSP-1 expression was not associated with microvessel density. However, RASSF1-A hypermethylation was more frequent in T1 tumours (P = 0.01), and p16 hypermethylation was not associated with any of the tested variables except for absence of p16 expression (P = 0.022). CONCLUSION: In summary, the epigenetic inactivation of TSP-1 and RASSF1-A genes is associated with pathological variables and seems to be of prognostic significance in penile cancer.

[Multifocal basaloid squamous carcinoma of the esophagus]. / Carcinoma basaloide escamoso multifocal de esófago.

Basaloid-squamous carcinoma is a poorly-differentiated variety of squamous cell carcinoma. The most common location is the upper aerodigestive tract and the incidence of this entity in the esophagus is low. Despite advances in knowledge of the biology of these tumors, their recent description and their low frequency has hampered consensus on the therapeutic approach. We present a case of basaloid-squamous cell of the esophagus a 54 year-old man who underwent an esophagectomy with lymphadenectomy and has been followed-up for 5 years with no evidence of disease recurrence. We also provide a literature review of this entity.

Efficient DNA extraction from 25-year-old paraffin-embedded tissues: study of 365 samples.

AIMS: Archival fixed paraffin-embedded tissue (PET) is a valuable source for population-based molecular genetic studies but the extraction of high quality DNA is still a problematic issue. The present study tested the grade of DNA fragmentation and the DNA adequacy for genetic investigations in a large series of tissue specimens that were formalin- or Bouin-fixed and paraffin-embedded between 1979 and 1983. Specific aims were to: (1) estimate the amount of archival tissue samples from which DNA is recoverable by conventional methods and the influence of variables (origin, fixative, section size) on DNA recovery; and (2) evaluate the feasibility of genetic investigations in large scale population studies. METHODS: DNA was extracted in 2005 from 365 PET samples from Italy and Spain and subjected to PCR analysis targeting fragments of 152, 268 and 676 bp of the beta-globin gene. RESULTS: Amplification of a 152 bp fragment was obtained in 252/365 (69%) PET samples, a 268 bp fragment in 62/365 (17%), a 676 bp fragment in 19/365 (5%) and no amplification for any fragment was obtained in 113/365 (31%). A second processing of newly cut sections performed in a 25% simple random sample gave comparable results, with substantial concordance between the first and second tests (kappa value 0.62 [95% CI 0.59-0.64]). CONCLUSIONS: The results of this study show that DNA can be efficiently extracted from PETs archived for more than 20 years, and that large scale population studies based on PCR amplification of short target sequences are feasible.

CAPN3 mutations in patients with idiopathic eosinophilic myositis.

OBJECTIVE: Eosinophilic myositis (EM) constitutes a rare pathological entity characterized by eosinophilic infiltration of skeletal muscles, usually associated with parasite infections, systemic disorders, or the intake of drugs or L-tryptophan. The exclusion of such causes defines the spectrum of idiopathic EM. Based on a protein analysis performed in one affected patient, we identified the gene encoding calpain-3, CAPN3, as a candidate for a subset of idiopathic EM. METHODS: We screened CAPN3 for mutations using DHPLC and direct sequencing in six unrelated patients, recruited for EM diagnosed after histological examination of muscle biopsy samples, without any identified causative factor. RESULTS: We identified CAPN3 mutations in the six unrelated patients originally diagnosed with idiopathic EM. INTERPRETATION: Mutations in CAPN3 can cause EM. Thus, a subset of idiopathic EM is genetically determined, with an autosomal recessive mode of inheritance. Patients presented with a triad that appears to be indicative of CAPN3 mutations: (1) EM in the first decade, (2) elevated serum creatine phosphokinase levels (isolated or with little corresponding weakness), and (3) inconstant peripheral hypereosinophilia. However, that EM represents a distinct phenotype associated to CAPN3 mutations or, rather, an early histopathological picture of LGMD2A must be further evaluated. Our findings should be of interest toward further investigating the role of calpain-3 in skeletal muscle. Furthermore, patients with idiopathic EM should undergo calpain-3 protein analysis and be considered for subsequent molecular analysis of the CAPN3 gene.