Giant Cell Tumor of Bone

This case is the first to elucidate the putative resistance mechanisms to zongertinib in HER2-mutant lung adenocarcinoma might be transformation of adenosquamous with giant-cell carcinoma and acquired HER2 amplification through integrated histological and molecular analyses. These findings highlight the necessity of post-progression biopsy and genomic profiling to characterize resistance evolution and guide subsequent therapy selection.

This case suggests that MGCTB may be an unrecognized source of ectopic β-hCG secretion. Clini-cians should consider this possibility in similar contexts to avoid misdiagnosis and unnecessary interventions.

P2, N=20, Not yet recruiting, Merck Healthcare KGaA, Darmstadt, Germany, an affiliate of Merck KGaA, Darmstadt, Germany

Although representing just 5% of all identified factors, these appeared in 69% of the included studies, highlighting their prominence in the literature. Apart from the well-known osteoclastogenesis factor CSF1, inflammatory cytokines (TNF-α and IL-1β) and monocyte-macrophage lineage makers (CD68, CD163) are signalling pathways key to TGCT disease progression and associated bone destruction.

Recent examples include spindle cell rhabdomyosarcomas with TFCP2 fusions, keratin-positive giant-cell rich tumors with HMGA2::NCOR2 fusions, NR1D1- rearranged sarcomas, malignant epithelioid neoplasms with FET::CREB fusions, and the very recently described ossifying spindled and epithelioid tumors (OSET). This review will address the unique clinical, histologic, and immunophenotypic characteristics of these rare neoplasms and provide practical considerations for molecular testing in challenging cases of keratin-positive mesenchymal neoplasia.

These studies indicate that GCTB not only induces osteoclasts, but also possesses activity that inhibits bone formation.

P3, N=123, Active, not recruiting, Deciphera Pharmaceuticals, LLC | Trial completion date: Jul 2026 --> Jul 2028

The remaining patients were alive and well at 16 to 33 months. MPC represents a distinct clinicopathological entity with frequent c-MYC amplification and may benefit from targeted MYC inhibition.

Proteomic analysis revealed that NCC-GCTB16-C1 exhibited properties similar to those of the original tumor tissue. Thus, NCC-GCTB16-C1 provides an in vitro model that faithfully reflects the molecular and phenotypic features of GCTB, offering a valuable tool for mechanistic studies and preclinical drug evaluation.

Percentage of spindled pattern and primary tumor diameter are potential prognostic factors for recurrence and metastasis, respectively, in GCTB.

CSF1R inhibitor can inhibit the tumor growth of recurrent GCTB. Targeting CSF1R and alleviating T cell exhaustion may provide therapeutic insights for the management of relapsed GCTB following DMAb discontinuation.

The targeted inhibition of osteoclast activity with denosumab has transformed clinical management, inducing profound morphological changes and bone formation...Collectively, GCTB exemplifies a molecularly defined bone tumor in which advances in epigenetic biology and tumor-microenvironment interactions have directly influenced diagnostic practice and therapeutic strategy. Ongoing challenges include refining risk stratification, optimizing treatment sequencing, and clarifying the biological consequences of sustained osteoclast suppression.