Pediatric Sarcomas

Pediatric Sarcomas2020-12-07T14:48:57+01:00
Anaplastic rhabdomyosarcoma, a type of pediatric sarcoma, in TP53 germline mutation carrier.

Anaplastic rhabdomyosarcoma in TP53 germline mutation carrier. Image taken from Hettmer et al, Cancer, 2014.

PD Dr. Simone Hettmer

T: +49-761-270-45480

Medical Center – University of Freiburg
Center for Pediatrics
Department of Pediatric Hematology and Oncology
Mathildenstraße 1
79106 Freiburg

Soft-tissue sarcomas are an important challenge in pediatric oncology. These tumors form a heterogeneous group of cancers of non-hematopoietic, mesodermal tissues. They are disproportionately common in children and adolescents. Most patients with high-risk metastatic disease die despite intensive therapy, and those who survive face lifelong, significant late effects of treatment.

Work in the Pediatric Sarcoma Laboratory aims at a better understanding of the cellular, molecular and metabolic underpinnings of sarcomas, which is a prerequisite for improving the diagnostic classification, risk stratification and therapy of these devastating cancers.

The basic research in the Pediatric Sarcoma Laboratory is complemented by close interaction with the Co-operative Soft Tissue Sarcoma Study Group, which is led by Simone Hettmer under the auspices of the German Society for Pediatric Oncology and Hematology.




Current research in our group includes the following projects:

Plasticity of PAX3:FOXO1 fusion-positive RMS

PAX3:FOXO1 expression in alveolar RMS fluctuates at the single cell level. Our ongoing work aims at demonstrating that PAX3:FOXO1 expression levels correlate with key determinants of malignant behavior and susceptibility to compounds with anti-sarcoma activity.

Asparagine dependence of sarcomas

Sarcoma growth depends on sufficient availability of the non-essential amino acid asparagine. Asparaginase reduces asparagine availability and sarcoma growth. The compensatory mechanisms, utilized by sarcoma cells to counteract the effects of asparagine deprivation, may serve as targets for combination therapies. To modulate asparagine availability in sarcoma cells, we are using lentivirally delivered shRNAs to knock down asparagine synthetase, and we are exposing cells to different concentrations of asparagine. Global metabolomics changes are being evaluated by mass spectrometry to identify actionable adaptive mechanisms. (Moritz Petzold, cand. med.)

Sarcoma predisposition

Recent evidence supports that 12-19% of all sarcomas arise in the context of monogenic, cancer-predisposing germline lesions. We are working on risk assessment tools to identify children with sarcoma-predisposing germline conditions based on full consideration of cancer history, sarcoma manifestation and sarcoma genotype. (Julia Würtemberger, MD & Manching Ku, PhD)

TP53 in RMS

We are investigating the impact of aberrant TP53, introduced at different time points during tumor evolution, on rhabdomyosarcoma phenotype, target expression and treatment susceptibility. (Ebrahem Hamed, PhD student)

For information about our pediatric sarcoma/sarcoma predisposition clinic, please visit the Sarcoma Clinic pages on the website of the Freiburg Center for Pediatrics and Adolescent Medicine.


Complete list of published works by Simone Hettmer:



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