Rhabdomyosarcoma

Unlike transient inflammation seen with conventional vaccines, WT1 vaccination induces prolonged FDG uptake due to the oil-based adjuvant Montanide, causing chronic inflammation and granuloma formation. Recognition of this characteristic course is essential to avoid misdiagnosis as cutaneous metastasis.

P1, N=20, Active, not recruiting, Valent Technologies, LLC | Recruiting --> Active, not recruiting

The histomorphologic heterogeneity of PPB resulted in a variety of non-PPB diagnoses among cases not initially classified as PPB. Molecular testing may clarify the diagnosis and provide prognostic and therapeutic insights.

P1/2, N=90, Recruiting, St. Jude Children's Research Hospital | Trial primary completion date: Dec 2025 --> Dec 2026

Immunohistochemical analysis showed diffuse positivity for desmin and MYOD1, with focal positivity for myogenin and a MKI67 proliferation index of 30%, leading to a final diagnosis of embryonal rhabdomyosarcoma with spindle cell morphology (ERMS). This study highlights the rarity of this presentation and underscores the critical role of immunohistochemical markers in the accurate diagnosis of ERMS at unusual locations.

Genetic or pharmacological inhibition of IRE1α or spliced XBP1 (sXBP1) suppresses cell proliferation, promotes terminal myogenic differentiation, and enhances vincristine-induced cytotoxicity in RMS cells...Consistently, inducible knockdown of sXBP1 or pharmacological inhibition of IRE1α endonuclease activity significantly attenuates xenograft RMS growth. Collectively, these findings identify the IRE1α-XBP1 axis as a critical regulator of RMS growth, differentiation, and chemosensitivity, and support its therapeutic targeting in RMS.

Genetic or pharmacological inhibition of IRE1α or spliced XBP1 (sXBP1) suppresses cell proliferation, promotes terminal myogenic differentiation, and enhances vincristine-induced cytotoxicity in RMS cells...Consistently, inducible knockdown of sXBP1 or pharmacological inhibition of IRE1α endonuclease activity significantly attenuates xenograft RMS growth. Collectively, these findings identify the IRE1α-XBP1 axis as a critical regulator of RMS growth, differentiation, and chemoresistance, and support its therapeutic targeting in RMS.

P1/2, N=30, Not yet recruiting, The University Of Birmingham

We emphasize distinguishing features from papillary urothelial carcinoma, mixed -epithelialstromal tumor/SMART, rhabdomyosarcoma, and -translocationassociated mesenchymal neoplasms, noting that focal -fibroadenomalike- stromal areas can occur in FEPs. Recognition of the confined polypoid growth beneath intact urothelium, bland cytology, and supportive immunomorphology, and selective molecular testing when stromal atypia raises concern, can avoid misclassification and unnecessary radical surgery.

P1, N=18, Enrolling by invitation, The Hospital for Sick Children | Trial completion date: Dec 2025 --> Jun 2027 | Trial primary completion date: Jun 2025 --> Dec 2026

P1, N=68, Active, not recruiting, Seattle Children's Hospital | Trial primary completion date: Dec 2025 --> Dec 2040

We demonstrate marked tumor growth inhibition in all FP-RMS PDXs treated with single-agent FGF401 (FGFR4-specific inhibitor) and single-agent lenvatinib (multikinase FGFR inhibitor) and report a clinical response to lenvatinib in a patient with relapsed metastatic FP-RMS. Altogether, we identified new patients with sarcoma who may benefit from FGFR inhibitors, most notably FP-RMS via FGFR4/FGF8 coexpression.