Proteomic profiling of soft tissue sarcomas with SWATH mass spectrometry.

Soft tissue sarcomas (STS) are a group of rare and heterogeneous cancers. While large-scale genomic and epigenomic profiling of STS have been undertaken, proteomic analysis has thus far been limited. Here we utilise sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) for proteomic profiling of formalin fixed paraffin embedded (FFPE) specimens from a cohort of STS patients (n = 36) across four histological subtypes (leiomyosarcoma, synovial sarcoma, undifferentiated pleomorphic sarcoma and dedifferentiated liposarcoma). We quantified 2951 proteins across all cases and show that there is a significant enrichment of gene sets associated with smooth muscle contraction in leiomyosarcoma, RNA splicing regulation in synovial sarcoma and leukocyte activation in undifferentiated pleomorphic sarcoma. We further identified a subgroup of STS cases that have a distinct expression profile in a panel of proteins, with worse survival outcomes when compared to the rest of the cohort. Our study highlights the value of comprehensive proteomic characterisation as a means to identify histotype-specific STS profiles that describe key biological pathways of clinical and therapeutic relevance; as well as for discovering new prognostic biomarkers in this group of rare and difficult-to-treat diseases.

Pazopanib in advanced soft tissue sarcomas.

Pazopanib is the first and only tyrosine kinase inhibitor currently approved for the treatment of multiple histological subtypes of soft tissue sarcoma (STS). Initially developed as a small molecule inhibitor of vascular endothelial growth factor receptors, preclinical work indicates that pazopanib exerts an anticancer effect through the inhibition of both angiogenic and oncogenic signaling pathways. Following the establishment of optimal dosing and safety profiles in early phase studies and approval for the treatment of advanced renal cell carcinoma, pazopanib was investigated in STS. A landmark phase III randomized study demonstrated improved progression-free survival with pazopanib compared to that with placebo in pretreated patients with STS of various subtypes. The efficacy of pazopanib in specific STS subtypes has been further described in real-world-based case series in both mixed and subtype-specific STS cohorts. At present, there are no clinically validated predictive biomarkers for use in selecting patients with advanced STS for pazopanib therapy, limiting the clinical effectiveness and cost-effectiveness of the drug. In this review, we summarize the preclinical and clinical data for pazopanib, outline the evidence base for its effect in STS and explore reported studies that have investigated putative biomarkers.

Clinical Characteristics and efficacy of chemotherapy in sclerosing epithelioid fibrosarcoma.

BACKGROUND: Sclerosing epithelioid fibrosarcoma (SEF) is a very rare soft tissue sarcoma subtype. Clinically it is an aggressive tumour; however, to our knowledge there are no published reports regarding the efficacy of chemotherapy in SEF. Therefore, the aim of this study was to document the outcome of a series of patients with SEF treated at a single referral centre with reference to systemic therapy. METHODS: A retrospective search of a prospectively maintained database was performed to identify all patients diagnosed with SEF between 1990 and 2017. The diagnosis was confirmed in each case by a dedicated soft tissue sarcoma pathologist. We analysed those with recurrent disease and the effect of systemic chemotherapy in the metastatic setting. RESULTS: Thirteen patients were identified, median overall survival from diagnosis and metastasis were 47.3 (95% CI 25.0-131.9) and 16.3 (95% CI 5.3-20.6) months, respectively. In total, 12 (92.3%) patients developed metastatic disease of which 10 died of disease, 1 was lost to follow-up and 1 had recently commenced palliative treatment. Among the 10 patients with metastatic disease, 7 received palliative chemotherapy. Palliative chemotherapy resulted in partial response in 1 patient, stable disease in 3 patients and progressive disease in 3 patients. Median time to disease progression was 2.7 (95% CI 1.2-4.4) months. Two of 13 patients were treated with adjuvant chemotherapy, receiving 6 cycles of liposomal doxorubicin and 1 cycle of doxorubicin, respectively, with a metastasis-free survival of 28.2 and 7.1 months, respectively. CONCLUSION: SEF is an aggressive sarcoma subtype with a poor outcome and with limited responsiveness to conventional chemotherapy. Patients with this subtype should be considered for participation in clinical trials with novel agents. Further investigation into the biology of this rare disease is required to improve outcomes.

2018 ESMO Sarcoma and GIST Symposium: 'take-home messages' in soft tissue sarcoma.

The 7th edition of the 'ESMO Sarcoma and GIST Symposium' was held in Milan in February 2018. For the first time, the Symposium brought together representatives from the European Reference Network on rare adult solid cancer (EURACAN) joined by sarcoma experts from the USA, Japan and patient advocacy groups, to share insights and discuss future directions in this rare condition. This commentary will summarise the highlights in soft tissue sarcomas.