Liposarcoma

BackgroundThe advent of immune checkpoint therapy has been a tremendous advance in cancer treatment. However, the responses are still insufficient in patients with soft tissue sarcoma (STS). We aimed to identify rational combinations to increase the response to immune checkpoint therapy and improve survival.MethodsWhole-exome sequencing (WES) was performed in 11 patients with liposarcoma. Somatic copy number alterations (SCNAs) were analyzed at the gene level to identify obvious amplification patterns in drug-target genes. The expression and prognostic value of class I histone deacetylases (HDACs) was evaluated in 49 patients with sarcoma in our center and confirmed in 263 sarcoma samples from The Tumor Cancer Genome Atlas (TCGA) database. Q-PCR, flow cytometry and RNA-seq were performed to determine the correlations between class I HDACs, chidamide and PD-L1 in vitro and in vivo. The efficacy of combining chidamide with PD-1 blockade was explored in an immunocompetent murine model and a small cohort of patients with advanced sarcoma. Western blot, ChIP assay and dual luciferase assessment were applied in the mechanistic study.ResultsThe HDAC gene family was frequently amplified in STS. SCNAs in the HDAC gene family were extensively amplified in 8 of 11 (73%) patients with liposarcoma, based on a drug-target gene set, and we verified amplification in 76.65% (197/257) of cases by analyzing TCGA sarcoma cohort. Class I HDAC expression is associated with a poor prognosis for patients with STS, and its inhibition is responsible for promoting apoptosis and upregulating of programmed cell death ligand 1 (PD-L1). The HDAC class I inhibitor chidamide significantly increases PD-L1 expression, increased the infiltration of CD8+ T cells and reduced the number of MDSCs in the tumor microenvironment. The combination of chidamide with an anti-PD-1 antibody significantly promotes tumor regression and improves survival in a murine model. Moreover, chidamide combined with the anti-PD-1 antibody toripalimab is effective in patients with advanced and metastatic sarcoma, and the side effects are tolerable. Mechanistically, chidamide increases histone acetylation at the PD-L1 gene through the activation of the transcriptional factor STAT1.ConclusionsThe combination of chidamide and anti-programmed cell death 1 (PD-1) therapy represents a potentially important strategy for STS.

The genomic characteristics of dedifferentiated liposarcoma (DDLPS) that are associated with clinical features remain to be identified. Here, we conduct integrated whole exome and RNA sequencing analysis in 115 DDLPS tumors and perform comparative genomic analysis of well-differentiated and dedifferentiated components from eight DDLPS samples. Several somatic copy-number alterations (SCNAs), including the gain of 12q15, are identified as frequent genomic alterations. CTDSP1/2-DNM3OS fusion genes are identified in a subset of DDLPS tumors. Based on the association of SCNAs with clinical features, the DDLPS tumors are clustered into three groups. This clustering can predict the clinical outcome independently. The comparative analysis between well-differentiated and dedifferentiated components identify two categories of genomic alterations: shared alterations, associated with tumorigenesis, and dedifferentiated-specific alterations, associated with malignant transformation. This large-scale genomic analysis reveals the mechanisms underlying the development and progression of DDLPS and provides insights that could contribute to the refinement of DDLPS management.

Rare cancers, affecting 1 in 5 cancer patients, disproportionally contribute to cancer mortality. This research focuses on liposarcoma, an understudied rare cancer with unknown risk factors and limited treatment options. Liposarcoma incident cases were identified from the U.S. Surveillance, Epidemiology, and End Result (SEER) program and the combined SEER-National Program of Cancer Registries (CNPCR) between 2001-2016. Incidence rates (age-adjusted and age-specific), 5-year survival, and the time trends were determined using SEER*stat software. Three-dimensional visualization of age-time curves was conducted for males and females. SEER liposarcoma cases represented ~30% (n = 11,162) of the nationwide pool (N = 37,499). Both sources of data showed males accounting for ~60% of the cases; 82%-86% cases were identified among whites. Age-adjusted incidence was greater among males vs. females and whites vs. blacks, whereas survival did not differ by sex and race. The dedifferentiated (57.2%), pleomorphic (64.1%), and retroperitoneal (63.9%) tumors had the worse survival. Nationwide, liposarcoma rates increased by 19%, with the annual percent increase (APC) of 1.43% (95% confidence interval (CI): 1.12-1.74). The APC was greater for males vs. females (1.67% vs. 0.89%) and retroperitoneal vs. extremity tumors (1.94% vs. 0.58%). Thus, incidence increased faster in the high-risk subgroup (males), and for retroperitoneal tumors, the low-survival subtype. The SEER generally over-estimated the rates and time trends compared to nationwide data but under-estimated time trends for retroperitoneal tumors. The time trends suggest an interaction between genetic and non-genetic modifiable risk factors may play a role in the etiology of this malignancy. Differences between SEER and CNCPR findings emphasize the need for nationwide cancer surveillance.

BackgroundRetroperitoneal sarcoma (RPS) is a type of malignant tumour arising from mesenchymal tissues within the retroperitoneal space. RPSs tend to develop covertly and are often undiscovered when they have already grown significantly and invaded surrounding tissues and organs. These malignancies demonstrate high recurrence rates, present surgical challenges and exhibit limited responsiveness to radiotherapy and chemotherapy. Serum-derived molecules are known to play critical roles in tumourigenesis and tumour progression. However, the serum molecular profile of RPS patients remains unclear.MethodsWe performed multi-omics analysis of serum samples from patients with retroperitoneal dedifferentiated liposarcoma. Prolactin concentrations were quantified using Enzyme-Linked Immunosorbent Assay (ELISA). RNA-seq facilitated the identification of candidate signalling pathways, while gene expression was validated through quantitative polymerase chain reaction, immunohistochemistry and western blot analyses. Molecular mechanisms underlying transcriptional regulation were investigated through Chromatin Immunoprecipitation-qPCR (ChIP-qPCR) and dual-luciferase reporter gene assays.ResultsIntegrative multi-omics profiling identified significant perturbations in galactose metabolism coupled with marked elevation of prolactin (PRL) levels in Retroperitoneal Liposarcoma (RLPS) patients. Further screening of serum prolactin levels in 100 patients with retroperitoneal tumours revealed that 90% of the cases exhibited hyperprolactinaemia in our research cohort, encompassing both malignant sarcomas and benign tumours. Studies at the clinical sample, cellular and animal levels have found that abnormally elevated prolactin in the serum can originate from sarcoma tissues. Mechanistic investigations identified SRY-box transcription factor 4 (SOX4) as a previously unrecognised transcriptional regulator of PRL. Functionally, PRL not only enhanced liposarcoma cell and fibrosarcoma cell proliferation but also conferred resistance to MDM2 inhibitors. Signalling pathway analysis revealed that PRL activates the Janus Kinase-Signal Transducer and Activator of Transcription Pathway (JAK-STAT) signalling pathway and up-regulates c-MYC expression.ConclusionsThis study indicates that PRL can serve as an oncogenic driver and therapeutic target. The identification of SOX4-PRL-c-MYC signalling axis provides actionable insights for developing novel therapeutic strategies against this malignancy.Key pointsRetroperitoneal sarcoma cells can secrete prolactin into the bloodstream, inducing hyperprolactinaemia, which subsequently triggers metabolic reprogramming, such as glucose metabolism. SOX4 can function as a transcription factor that facilitates PRL transcription. PRL can activate the JAK-STAT signalling pathway by binding to PRLR on sarcoma cells, leading to the up-regulation of c-MYC.