Leiomyosarcoma (LMS) is an aggressive mesenchymal malignancy with few therapeutic options. The mechanisms underlying LMS development, including clinically actionable genetic vulnerabilities, are largely unknown. Here we show, using whole-exome and transcriptome sequencing, that LMS tumors are characterized by substantial mutational heterogeneity, near-universal inactivation of TP53 and RB1, widespread DNA copy number alterations including chromothripsis, and frequent whole-genome duplication. Furthermore, we detect alternative telomere lengthening in 78% of cases and identify recurrent alterations in telomere maintenance genes such as ATRX, RBL2, and SP100, providing insight into the genetic basis of this mechanism. Finally, most tumors display hallmarks of “BRCAness”, including alterations in homologous recombination DNA repair genes, multiple structural rearrangements, and enrichment of specific mutational signatures, and cultured LMS cells are sensitive towards olaparib and cisplatin. This comprehensive study of LMS genomics has uncovered key biological features that may inform future experimental research and enable the design of novel therapies.

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BackgroundSpinal bone metastases are commonly diagnosed in cancer patients. The consequences are pain both at rest and under exercise, impairment of activities of daily life (ADL), reduced clinical performance, the risk of pathological fractures, and neurological deficits. The aim of this randomized, controlled pilot trial was to investigate the feasibility of muscle-training exercises in patients with spinal bone metastases under radiotherapy. Secondary endpoints were local control, pain response and survival.MethodsThis study was a prospective, randomized, monocentre, controlled explorative intervention trial to determine the multidimensional effects of exercises for strengthening the paravertebral muscles. On the days of radiation treatment, patients in the control group were physically treated in form of respiratory therapy. Sixty patients were randomized between September 2011 and March 2013 into one of the two groups: differentiated resistance training or physical measure with thirty patients in each group.ResultsThe resistance training of the paravertebral muscles was feasible in 83.3% of patients (n = 25). Five patients died during the first three months. The exercise group experienced no measurable side effects. “Chair stand test” in the intervention group was significant enhanced with additionally improved analgesic efficiency. Patients in intervention group improved in pain score (VAS, 0–10) over the course (p < .001), and was significant better between groups (p = .003) after 3 months. The overall pain response showed no significant difference between groups (p = .158) There was no significant difference in overall and bone survival (survival from first diagnosed bone metastases to death).ConclusionsOur trial demonstrated safety and feasibility of an isometric resistance training in patients with spinal bone metastases. The results offer a rationale for future large controlled investigations to confirm these findings.Trial registrationClinical trial identifier NCT01409720.