Biphenotypic sinonasal sarcoma—A recently described entity with many mimics: A case report

Biphenotypic sinonasal sarcoma (BSNS) is a recently described, low-grade, slow-growing sarcoma with neural and myogenic features with exclusive location in sinonasal track and characteristic PAX3- MAML3 gene fusion. Differentiating this tumor from its commoner mimics needs knowledge of this entity to avoid over treatment. This tumor has unique morphology, clinical course, and genetics. We report this in a 47-year-old female who was diagnosed with such a rare, solitary fibrous tumor—hemangiopericytoma (HPC-SFT) on limited initial biopsy. On subsequent excision, typical morphology and immunohistochemistry helped to clinch the diagnosis.

Gene mutation analysis in a Chinese pedigree with autosomal dominant Waardenburg syndrome / 中华皮肤科杂志

Objective:To report a Chinese pedigree with autosomal dominant Waardenburg syndrome, and to identify causative gene mutations.Methods:Clinical data and peripheral blood samples were collected from the proband and her parents. Genomic DNA was extracted, gene mutations were detected through a next-generation skin-targeted sequencing panel, and Sanger sequencing was performed to verify causative mutations.Results:The proband clinically presented with irregular white patches on the abdomen and lower limbs, moderate to severe sensorineural deafness in the right ear, and iris heterochromia in both eyes. The proband′s mother presented with iris heterochromia in both eyes, epicanthus, early canities and thick eyebrows. In the family, both the proband and her mother were diagnosed with Waardenburg syndrome. A causative frameshift mutation c.976-977delinsT (p.Thr327Profs*54) was identified in both the proband and her mother, which caused the AG to TT base substitution at positions 976 - 977 in the coding region of exon 7 of the PAX3 gene, resulted in a frameshift from the amino acid position 327 to 54 in the PAX3 protein (threonine was substituted by proline at amino acid position 327). The proband′s father showed a normal phenotype, and his genetic test results were negative.Conclusion:The novel frameshift mutation c.976-977delinsT (p.Thr327Profs*54) in the PAX3 gene may contribute to the clinical phenotype of the patients with Waardenburg syndrome in the family.

MicroRNA-206 Reduces Osteosarcoma Cell Malignancy In Vitro by Targeting the PAX3-MET Axis

PURPOSE: This study was undertaken to explore how miR-206 represses osteosarcoma (OS) development. MATERIALS AND METHODS: Expression levels of miR-206, PAX3, and MET mRNA were explored in paired OS and adjacent tissue specimens. A patient-derived OS cell line was established. miR-206 overexpression and knockdown were achieved by lentiviral transduction. PAX3 and MET overexpression were achieved by plasmid transfection. Treatment with hepatocyte growth factor (HGF) was utilized to activate c-Met receptor. Associations between miR-206 and PAX3 or MET mRNA in OS cells were verified by AGO2-RNA immunoprecipitation assay and miRNA pulldown assay. OS cell malignancy was evaluated in vitro by cell proliferation, metastasis, and apoptosis assays. PAX3 and MET gene expression in OS cells was assayed by RT-qPCR and Western blot. Activation of PI3K-AKT and MAPK-ERK in OS cells were assayed by evaluating Akt1 Ser473 phosphorylation and total threonine phosphorylation of Erk1/2, respectively. RESULTS: Expression levels of miR-206 were significantly decreased in OS tissue specimens, compared to adjacent counterparts, and were inversely correlated with expression of PAX3 and MET mRNA. miR-206 directly interacted with PAX3 and MET mRNA in OS cells. miR-206 overexpression significantly reduced PAX3 and MET gene expression in OS cells in vitro, resulting in significant decreases in Akt1 and Erk1/2 activation, cell proliferation, and metastasis, as well as increases in cell apoptosis, while miR-206 knockdown showed the opposite effects. The effects of miR-206 overexpression on OS cells were reversed by PAX3 or MET overexpression, but only partially attenuated by HGF treatment. CONCLUSION: miR-206 reduces OS cell malignancy in vitro by targeting PAX3 and MET gene expression.

Identification of a Novel De Novo Variant in the PAX3 Gene in Waardenburg Syndrome by Diagnostic Exome Sequencing: The First Molecular Diagnosis in Korea

Waardenburg syndrome (WS) is a clinically and genetically heterogeneous hereditary auditory pigmentary disorder characterized by congenital sensorineural hearing loss and iris discoloration. Many genes have been linked to WS, including PAX3, MITF, SNAI2, EDNRB, EDN3, and SOX10, and many additional genes have been associated with disorders with phenotypic overlap with WS. To screen all possible genes associated with WS and congenital deafness simultaneously, we performed diagnostic exome sequencing (DES) in a male patient with clinical features consistent with WS. Using DES, we identified a novel missense variant (c.220C>G; p.Arg74Gly) in exon 2 of the PAX3 gene in the patient. Further analysis by Sanger sequencing of the patient and his parents revealed a de novo occurrence of the variant. Our findings show that DES can be a useful tool for the identification of pathogenic gene variants in WS patients and for differentiation between WS and similar disorders. To the best of our knowledge, this is the first report of genetically confirmed WS in Korea.

Generation and Expression of Recombinant Eukaryotic Expression Plasmids of PAX3 Gene and Its Significance / 听力学及言语疾病杂志

Objective To study exogenous expression and subcellular localization of wild type (WT ) and mu-tant PAX3 proteins in vitro by generating their expression plasmids for further study of pathogenesis of Waarden-burg syndrome (WS) .Methods The plasmids pECE-PAX3 and pcDNA3 .0-HA were ligased after they were cut by double enzyme digestion using molecular cloning technique to generate recombinant eukaryotic expression plasmid pcDNA3 .0-PAX3-HA ,which was as a template to generate expression plasmids pcDNA 3 .0 -H80D -HA and pcDNA3 .0-H186fs-HA of novel mutations H80D and H186fs of PAX3 gene .All constructs were verified by di-rect nucleotide sequencing .NIH3T3 cells were transfected transiently with the expression plasmids of PAX3 ,H80D and H186fs respectively .The exogenous expression of WT PAX3 protein and mutant H80D ,H186fs proteins were analysed using Western blot assay ,while their subcellular distribution were observed using immunofluorescence as-say .Results The DNA sequences of expression plasmids of PAX3 and its mutant H80D ,H186fs were correct . Both WT and mutant PAX3 proteins were detected at the expected size .WT PAX3 and H80D proteins were only lo-calized in the nucleus ,whereas H186fs protein showed aberrant localization in both cytoplasm and nucleus .Conclu-sion We successfully generated the recombinant eukaryotic expression plasmids of PAX 3 gene and its mutants and drew preliminary conlusion of gene mutation having effect on subcellular distribution of WT PAX 3 proteins in vitro , which lays experimental basis for further study of the moceluar mechanism of WS caused by PAX3 gene mutations in China .

Three Cases of Waardenburg Syndrome Type 2 in a Korean Family

Waardenburg syndrome (WS) is a rare, autosomal dominant disorder characterized by sensorineural hearing loss, pigmentary disturbances of the skin, hair, and iris, and other developmental defects such as lateral displacement of both medial canthi and lacrimal puncta called dystopia canthorum. While mutations of the PAX3 (paired box) gene have been identified in about 99% of WS type 1 cases, WS type 2 is a heterogeneous group, with about 15% of cases caused by mutations in microphthalmia associated transcription factor (MITF). We have experienced three cases of typical WS type 2 in a Korean family, for whom full ocular examination and genetic studies were performed. The genetic studies revealed no mutation in either PAX3 or MITF genes. The genetic basis, as yet unknown for most cases of WS type 2, might be found with further investigation.