This retrospective study is looking into mechanisms of drug therapy resistance in FFPE samples in recurrent and refractory Rhabdomyosarcoma (RMS) in pediatric patients who have experienced lung recurrence. The study employs advanced techniques such as single-cell transcriptomics and spatial transcriptomics to gain a comprehensive understanding of these mechanisms.

This research seeks to enhance our understanding of drug resistance mechanisms in recurrent and refractory RMS in pediatric patients, particularly in the context of lung recurrence. The utilization of cutting-edge techniques like single-cell transcriptomics and spatial transcriptomics allows for a more in-depth and comprehensive analysis of the molecular and spatial aspects of drug resistance in this challenging pediatric cancer.

Inclusion Criteria:

1. Pediatric Patients: Participants in this study should be pediatric patients, typically defined as individuals aged from infancy to 18 years old, who have been diagnosed with recurrent and refractory Rhabdomyosarcoma (RMS).
2. Lung Recurrence: Included patients must have a documented history of lung recurrence of RMS as a specific clinical manifestation.
3. Availability of FFPE Samples: Patients for whom formalin-fixed paraffin-embedded (FFPE) tissue samples are available for analysis are eligible for inclusion.

Exclusion Criteria:

1. Other Histological Types: Patients with RMS of histological subtypes other than those relevant to the study focus are excluded.
2. Incomplete Clinical Data: Patients with incomplete or insufficient clinical data necessary for the study's objectives may be excluded to ensure robust analysis and interpretation of results.

All participants have previously been diagnosed with RMS, a rare and aggressive form of pediatric soft tissue cancer. Importantly, their RMS cases are characterized by recurrence, indicating that the cancer has returned after initial treatment, and refractoriness, meaning it has not responded well to standard therapies.

A defining feature of the study population is the presence of documented lung recurrence. This signifies that the RMS has re-emerged specifically within the lung tissue. Lung recurrence is a critical clinical aspect being investigated in this study.