This non-interventional study aims to develop spatial proteomics for analyzing small FFPE tumor samples in rhabdomyosarcoma. It will identify molecular signatures linked to tumor regions, subtypes, survival, and treatment resistance, using pre-existing samples and data.

This is a non-interventional, monocentric, retrospective cohort study aimed at developing a spatial proteomics analysis method for small tumor samples (FFPE) to precisely characterize proteins at the tissue level in rhabdomyosarcoma (RMS). Using mass spectrometry, the study will identify molecular signatures associated with different tumor regions, histological subtypes, patient survival, and treatment resistance. The goal is to identify potential protein biomarkers and therapeutic targets. Data from clinical samples will be analyzed to find biomarkers correlated with survival and resistance to treatment. No patient intervention is required, as the study uses pre-existing biological samples and clinical data.

Inclusion Criteria:

• Age between 0 and 25 years at the time of initial diagnosis
• Diagnosis of rhabdomyosarcoma confirmed histologically
• Care at the Oscar Lambret Center between January 2005 and November 2024
• No objection to the re-use of data and biological samples collected as part of care for research activities.

Exclusion Criteria:

• Unavailability of biological sample in FFPE from biopsy and/or surgical specimen for diagnosis at Centre Oscar Lambret;
• Patient under guardianship or trusteeship.

Oscar Lambret Center (Lille, France)