Spindle cell sarcoma with KIAA1549-BRAF resembling infantile fibrosarcoma morphologically: A case report and literature review.

Infantile fibrosarcoma (IFS) commonly harbors ETS variant transcription factor 6 (ETV6)-neurotrophic receptor tyrosine kinase 3 (NTRK3) fusion. However, the recent accessibility to clinical next-generation sequencing (NGS) has revealed ETV6-NTRK3 negative spindle cell sarcomas resembling IFS morphologically, involving NTRK1/2, MET, RET and BRAF. The present report describes a pediatric case of spindle cell sarcoma with KIAA1549-BRAF resembling IFS morphologically. A 20-month-old female patient was referred to Kobe Children's Hospital (Kobe, Japan) for the treatment of intrathoracic spindle cell sarcoma. Pathologically, the intrathoracic tumor cells were composed of spindle cells with focal hemagiopericytomatous pattern. In immunohistochemistry analysis, the intrathoracic tumor cells focally expressed desmin and WT-1 and were negative for pan-tropomyosin receptor kinase (TRK), S-100 and CD34. Fluorescence in situ hybridization analysis for ETV6 and capicua transcriptional repressor revealed negative split signals. Although the patient was initially diagnosed with IFS morphologically, KIAA1549-BRAF fusion transcript was detected by comprehensive genomic profiling with NGS using intrathoracic tumor tissues and confirmed by reverse transcription-PCR. Chemotherapy induced a reduction in the tumor size. At present, the patient is alive with the disease and has been receiving therapy for 8 months since the initiation of chemotherapy. Review of BRAF-altered spindle cell sarcomas resembling IFS morphologically revealed the inconsistency in immunohistochemical expression patterns and the diversity of BRAF fusion genes and mutations. Therefore, the elucidation of genomic profiling by NGS may assist in making an appropriate diagnosis and selecting novel alternative therapies in ETV6-NTRK3-negative spindle cell sarcomas resembling IFS morphologically.

Muraminomicins, novel ester derivatives: in vitro and in vivo antistaphylococcal activity.

Novel muraminomicin derivatives with antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) were synthesized by esterification of the hydroxy group on the diazepanone ring of muraminomicin Z1. Compound 1b (DS14450354) possessed a diheptoxybenzyl-ß-Alanyl-ß-Alanyl group and exhibited minimum inhibitory concentrations (MICs) against MRSA comparable to those against methicillin-susceptible S. aureus (MSSA). The MICs that inhibited 50 and 90% of the strains were 1 and 2 µg/mL, respectively. Compound 1a (DS60182922) possessed an aminoethylbenzoyldodecylglycyl moiety and showed bactericidal activity against MSSA Smith. The bactericidal activity of 1a against MRSA 10925 was comparatively lower, whilst 1b exhibited dose-dependent bactericidal activity against MRSA 10925. The mutation frequency of 1b was lower than that of 1a. An amino acid substitution (F226I) was observed in MraY mutants isolated from culture plates containing 1a or 1b. Subcutaneous 1a and 1b administration showed good therapeutic efficacy in murine systemic infection models with MSSA Smith and MRSA 10925, comparable to that of vancomycin, suggesting that the novel muraminomicin derivatives may be effective therapeutic agents against MRSA that warrant further investigation. A scheme for the formulation of the key ester intermediate, requiring no HPLC preparation, was also established.