Charles Walther

A novel SERPINE1-FOSB fusion gene results in transcriptional up-regulation of FOSB in pseudomyogenic haemangioendothelioma.

Pseudomyogenic haemangioendothelioma (PHE) is an intermediate malignant vascular soft tissue tumour primarily affecting children and young adults. The molecular basis of this neoplasm is unknown. We here used chromosome banding analysis, fluorescence in situ hybridization (FISH), mRNA sequencing, RT–PCR and quantitative real‐time PCR on a series of morphologically well‐characterized PHEs to show that a balanced translocation, t(7;19)(q22;q13), detected as the sole cytogenetic aberration in two cases, results in fusion of the SERPINE1 and FOSB genes. This translocation has not been observed in any other bone or soft tissue tumour. Interphase FISH on sections from eight additional PHEs identified the same SERPINE1–FOSB fusion in all cases. The role of SERPINE1, which is highly expressed in vascular cells, in this gene fusion is probably to provide a strong promoter for FOSB, which was found to be expressed at higher levels in PHEs than in other soft tissue tumours. FOSB encodes a transcription factor belonging to the FOS family of proteins, which, together with members of the JUN family of transcription factors, are major components of the activating protein 1 (AP‐1) complex. Further studies are needed to understand the cellular impact of the aberrant expression of the FOSB gene, but as the t(7;19) resulting in the SERPINE1–FOSB fusion seems to be pathognomonic for PHE, FISH or RT–PCR could be useful for differential diagnostic purposes. Published by John Wiley & Sons, Ltd. www.pathsoc.org.uk

Increasing Prevalence of Adenocarcinoma of the Oesophagus and Gastro-Oesophageal Junction: A Study of the Swedish Population Between 1970 and 1997

OBJECTIVE To see whether there was an increasing incidence of adenocarcinoma of the oesophagus and gastric cardia in the Swedish population. If there is a rising trend and variations in it can be found, could it be explained as a period or cohort phenomenon? The data were also compared with the incidence of squamous cell carcinoma and gastric cancer with the gastric cardia excluded. DESIGN Retrospective study. SETTING Sweden. SUBJECTS Swedish population. MAIN OUTCOME MEASURES Age standardised incidence for each sex was calculated using the age distribution of the world population as a reference. Age-period-cohort models were fitted to data using Poisson regression to model log incidence rates. RESULTS For the combined group of adenocarcinoma in the oesophagus and gastric cardia age standardised incidence gradually increased during the study period. The median increase between adjacent five-year intervals was 20% in women and 14% in men. A period effect was evident in men. CONCLUSION This study shows that the incidence of adenocarcinoma of the oesophagus and gastroesophageal junction is rising for both men and women in the Swedish population. This is explained as a period effect. As well as previously-described risk factors such as gastro-oesophageal reflux, obesity, and smoking, the increasing incidence can be explained as a shift in classification from squamous cell carcinoma to adenocarcinoma after 1985.

Gene fusion detection in formalin-fixed paraffin-embedded benign fibrous histiocytomas using fluorescence in situ hybridization and RNA sequencing

Benign fibrous histiocytomas (FH) can be subdivided into several morphological and clinical subgroups. Recently, gene fusions involving either one of two protein kinase C genes (PRKCB and PRKCD) or the ALK gene were described in FH. We here wanted to evaluate the frequency of PRKCB and PRKCD gene fusions in FH. Using interphase fluorescence in situ hybridization on sections from formalin-fixed paraffin-embedded (FFPE) tumors, 36 cases could be analyzed. PRKCB or PRKCD rearrangements were seen in five tumors: 1/7 regular, 0/3 aneurysmal, 0/6 cellular, 2/7 epithelioid, 0/1 atypical, 2/10 deep, and 0/2 metastatic lesions. We also evaluated the status of the ALK gene in selected cases, finding rearrangements in 3/7 epithelioid and 0/1 atypical lesions. To assess the gene fusion status of FH further, deep sequencing of RNA (RNA-Seq) was performed on FFPE tissue from eight cases with unknown gene fusion status, as well as on two FH and six soft tissue sarcomas with known gene fusions; of the latter eight positive controls, the expected fusion transcript was found in all but one, while 2/8 FH with unknown genetic status showed fusion transcripts, including a novel KIRREL/PRKCA chimera. Thus, also a third member of the PRKC family is involved in FH tumorigenesis. We conclude that gene fusions involving PRKC genes occur in several morphological (regular, cellular, aneurysmal, epithelioid) and clinical (cutaneous, deep) subsets of FH, but they seem to account for only a minority of the cases. In epithelioid lesions, however, rearrangements of PRKC or ALK were seen, as mutually exclusive events, in the majority (5/7) of cases. Finally, the study also shows that RNA-Seq is a promising tool for identifying gene fusions in FFPE tissues.

Genetic heterogeneity in rhabdomyosarcoma revealed by SNP array analysis

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents. Alveolar (ARMS) and embryonal (ERMS) histologies predominate, but rare cases are classified as spindle cell/sclerosing (SRMS). For treatment stratification, RMS is further subclassified as fusion‐positive (FP‐RMS) or fusion‐negative (FN‐RMS), depending on whether a gene fusion involving PAX3 or PAX7 is present or not. We investigated 19 cases of pediatric RMS using high resolution single‐nucleotide polymorphism (SNP) array. FP‐ARMS displayed, on average, more structural rearrangements than ERMS; the single FN‐ARMS had a genomic profile similar to ERMS. Apart from previously known amplification (e.g., MYCN, CDK4, and MIR17HG) and deletion (e.g., NF1, CDKN2A, and CDKN2B) targets, amplification of ERBB2 and homozygous loss of ASCC3 or ODZ3 were seen. Combining SNP array with cytogenetic data revealed that most cases were polyploid, with at least one case having started as a near‐haploid tumor. Further bioinformatic analysis of the SNP array data disclosed genetic heterogeneity, in the form of subclonal chromosomal imbalances, in five tumors. The outcome was worse for patients with FP‐ARMS than ERMS or FN‐ARMS (6/8 vs. 1/9 dead of disease), and the only children with ERMS showing intratumor diversity or with MYOD1 mutation‐positive SRMS also died of disease. High resolution SNP array can be useful in evaluating genomic imbalances in pediatric RMS.

Cytogenetic and single nucleotide polymorphism array findings in soft tissue tumors in infants

Soft tissue tumors in children under one year of age (infants) are rare. The etiology is usually unknown, with external factors or congenital birth defects and hereditary syndromes being recognized in only a small proportion of the cases. We ascertained the cytogenetic findings in 16 infants from whom tumor tissue had been obtained during a 25-year period. In eight of them, single nucleotide polymorphism (SNP) array analyses could also be performed. No constitutional chromosome aberrations were detected, and assessment of clinical files did not reveal any congenital or later anatomical defects. Three tumors--one infantile fibrosarcoma, one embryonal rhabdomyosarcoma, and one angiomatoid fibrous histiocytoma (AFH)--had abnormal karyotypes. As the AFH had an exchange between chromosome arms 12p and 15q, additional fluorescence in situ hybridization and reverse transcription-polymerase chain reaction analyses were performed, unexpectedly revealing an ETV6/NTRK3 fusion. Three of the eight tumors, including the AFH with an abnormal karyotype, analyzed by SNP array showed aberrations (loss of heterozygosity or imbalances). The present series suggests that the addition of array-based technologies is valuable for detecting underlying pathogenetic mechanisms.

Biphasic, hyperdiploid breast tumors in children: a distinct entity?

Background: The differentiation between a giant fibroadenoma and a phyllodes tumor can be a precarious diagnostic task. However, the distinction between the 2 lesions is important to make, especially since the latter can be malignant and consequently the prognoses differ. Procedure: We used various genetic approaches to study a breast tumor showing features of both entities in a 10-year-old girl with a congenital cerebral malformation and diabetes mellitus. Results: Cytogenetic analysis of cultured tumor cells from 3 different samples revealed a hyperdiploid karyotype: 50-54,XX,+5,+13,+17,+18,+19,+20,+21. High-resolution single nucleotide polymorphism array analysis not only confirmed the trisomies, but also revealed uniparental disomy (UPD) for chromosomes 10, 11, and 22. A consequence of UPD11 was a homozygous deletion in chromosome band 11p15 affecting the PARVA gene; this gene was hemizygously lost in constitutional DNA. Extended analysis of the family revealed that the deletion was inherited, but it did not segregate with breast tumors or congenital malformations. Conclusions: Combined with the literature data, the findings in the present case strongly suggest that biphasic tumors with high hyperdiploid karyotypes constitute a distinct clinicomorphologic subgroup of benign breast tumors, being particularly common among young children.

Pericytic (Perivascular) Tumors

Genetics These exceedingly rare tumors and related genetic information are limited. Inactivation of the tumor suppressor NF1 on chromosome 17q has been observed in these tumors [6] . Apart from rearrangements involving 17q, NF1 -associated tumors have displayed both copy number changes and sometimes polyploidy [7] . Fluorescence in situ hybridization (FISH), single nucleotide polymorphism (SNP) array, and next-generation sequencing (NGS) can best visualize this rearrangement on fresh or fixed material.

Pseudomyogenic hemangioendothelioma: t(7;19)(q22;q13) SERPINE1/FOSB

Pseudomyogenic hemangioendothelioma (PHE) is an intermediate malignant vascular tumor primarily affecting soft tissues in children and young adults. The molecular basis of this neoplasm is unknown. Chromosome banding analysis, fluorescence in situ hybridization (FISH), mRNA sequencing, RT-PCR, and quantitative real-time PCR have shown that PHEs are characterized by a balanced translocation t(7;19)(q22;q13), resulting in the fusion of the SERPINE1 and FOSB genes. The role of SERPINE1, which is highly expressed in vascular cells, in this gene fusion is probably to provide a strong promoter for FOSB. FOSB encodes a transcription factor belonging to the FOS family of proteins, which together with members of the JUN family of transcription factors are major components of the Activating Protein 1 (AP-1) complex.

A New Method for Endoscopic Sampling of Submucosal Tissue in the Gastrointestinal Tract: A Comparison of the Biopsy Forceps and a New Drill Instrument

Background. Sampling of submucosal lesions in the gastrointestinal tract through a flexible endoscope is a well-recognized clinical problem. One technique often used is endoscopic ultrasound-guided fine-needle aspiration, but it does not provide solid tissue biopsies with preserved architecture for histopathological evaluation. To obtain solid tissue biopsies from submucosal lesions, we have constructed a new endoscopic biopsy tool and compared it in a crossover study with the standard double cupped forceps. Methods. Ten patients with endoscopically verified submucosal lesions were sampled. The endoscopist selected the position for the biopsies and used the instrument selected by randomization. After a biopsy was harvested, the endoscopist chose the next site for a biopsy and again used the instrument picked by randomization. A total of 6 biopsies, 3 with the forceps and 3 with the drill instrument, were collected in every patient. Results. The drill instrument resulted in larger total size biopsies (mm2; Mann-Whitney U test, P = .048) and larger submucosal part (%) of the biopsies (Mann-Whitney U test, P = .003) than the forceps. Two patients were observed because of chest pain and suspicion of bleeding in 24 hours. No therapeutic measures were necessary to be taken. Conclusion. The new drill instrument for flexible endoscopy can safely deliver submucosal tissue samples from submucosal lesions in the upper gastrointestinal tract.