Paediatric BCOR-associated sarcomas with a novel long spliced internal tandem duplication of BCOR exon 15.

Clear cell sarcoma of the kidney (CCSK) and primitive myxoid mesenchymal tumour of infancy (PMMTI) are paediatric sarcomas that most commonly harbour internal tandem duplications (ITDs) of exon 15 of the BCOR gene, in the range of 87-114 base pairs (bp). Some cases, instead, have BCOR-CCNB3 or YWHAE-NUTM2 gene fusions. About 10% of cases lack any of these genetic alterations when tested by standard methods. Two cases of CCSK and one PMMTI lacking the aforementioned mutations were analysed using Archer FusionPlex technology. Two related BCOR exon 15 RNA transcripts with ITDs of lengths 388 and 96 bp were detected in each case; only the 388 bp transcript was identified when genomic DNA was sequenced. In silico analysis of this transcript revealed acceptor and donor splice sites indicating that, at the RNA level, the 388-bp transcript was likely spliced to form the 96-bp transcript. The results were confirmed by Sanger sequencing using primers targeting the ITD breakpoint. This novel and unusually long ITD segment is difficult to identify by DNA sequencing using typical primer design strategies flanking entire duplicated segments because it exceeds the typical read lengths of most sequencing platforms as well as the usual fragment lengths obtained from formalin-fixed paraffin-embedded material. As diagnosis of CCSK and PMMTI may be challenging by morphology and immunohistochemistry alone, it is important to identify mutations in these cases. Knowledge of this novel BCOR ITD is important in relation to primer design for detection by sequencing, and using RNA versus DNA for sequencing.

ACE2 and TMPRSS2 in human saliva can adsorb to the oral mucosal epithelium.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is primarily transmitted through droplets. All human tissues with the angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serines 2 (TRMPRSS2) are potential targets of SARS-CoV-2. The role of saliva in SARS-CoV-2 transmission remains obscure. In this study, we attempted to reveal ACE2 and TRMPRSS2 protein expression in human parotid, submandibular, and sublingual glands (three major salivary glands). Then, the binding function of spike protein to ACE2 in three major salivary glands was detected. The expression of ACE2 and TMPRSS2 in human saliva from parotid glands were both examined. Exogenous recombined ACE2 and TMPRSS2 anchoring and fusing to oral mucosal epithelial cells in vitro were also unraveled. ACE2 and TMPRSS2 were found mainly to be expressed in the cytomembrane and cytoplasm of epithelial cells in the serous acinus cells in parotid and submandibular glands. Our research also discovered that the spike protein of SARS-CoV-2 binds to ACE2 in salivary glands in vitro. Furthermore, exogenous ACE2 and TMPRSS2 can anchor and fuse to oral mucosa in vitro. Thus, the expression of ACE2 and TMPRSS2 in human saliva might have implications for SARS-CoV-2 infection.