bims-myxlip Biomed News
on Myxoid liposarcoma
Issue of 2022‒06‒12
five papers selected by
Laura Mannarino
Humanitas Research

  1. J Assoc Genet Technol. 2022 ;48(2): 68-75
      OBJECTIVES: Myxoid/Round Cell Liposarcoma (MRCL) is characterized as a soft tissue sarcoma that is associated with unusual patterns of metastasis to extrapulmonary sites, such as bones and other soft tissue sites. Here, we present a case of a 48-year-old male patient, diagnosed with MRCL. The patient presented with a grade 1 myxoid liposarcoma in his left leg. DNA FISH analysis showed variant rearrangements of the EWSR1 (22q12) gene and loss of the 5' DDIT3 (CHOP 12q13) gene. The variant rearrangement showed one or two fusions with multiple separated (rearranged) signals. The EWSR1-DDIT3 rearrangement has been reported in MRCL. The variant rearrangements of the EWSR1 (22q12) gene findings correlate with concurrent conventional cytogenetic findings and were described as nuc ish(EWSR1x2) (5'EWSR1 sep 3'EWSR1x1)[128/100],(5'EWSR1,3'EWSR1)x1~3(5'EWSR1 con 3'EWSR1x1~2)[57/100]. The variant rearrangements of the DDIT3 (CHOP 12q13) gene findings were described as nuc ish(5'DDIT3x1,3'DDIT3x2)(5'DDIT3 con 3'DDIT3x1)[195/200]. Molecular cytogenetic studies also showed a rearrangement of EWSR1 (22q12) in 64% of nuclei and variant rearrangement in 31.5% of nuclei. A loss of DDIT3's (12q13) 5' signal was found in 97.5% of interphase nuclei. Molecular pathology results indicated the patient was positive for EWSR1 (exon 7) and DDIT3 (exon 2) fusion. The patient underwent radiation therapy pre-resection of the myxoid liposarcoma. The most common form of MRCL is associated with t(12;16)(q13;p11), leading to FUS-CHOP and EWS-CHOP fusion proteins acting as aberrant transcription factors. The key element here is that this EWSR1-DDIT3 rearrangement led to a translocation t(12;22)(q13;q12) which is a rare cytogenetic event that led to the development of MRCL in this patient.
  2. Cancers (Basel). 2022 May 25. pii: 2624. [Epub ahead of print]14(11):
      BACKGROUND: Well-differentiated (WD)/dedifferentiated (DD) liposarcoma (LPS) accounts for ~60% of retroperitoneal sarcomas. WDLPS and DDLPS divergently evolve from a common precursor and are both marked by the amplification of the 12q13-q15 region, leading to the abnormal expression of MDM2, CDK4, and HMGA2 genes. DDLPS is a non-lipogenic disease associated with aggressive clinical behavior. Patients have limited therapeutic options, especially for advanced disease, and their outcome remains largely unsatisfactory. This evidence underlines the need for identifying and validating DDLPS-specific actionable targets to design novel biology-driven therapies.METHODS: Following gene expression profiling of DDLPS clinical specimens, we observed the up-regulation of "telomere maintenance" (TMM) pathways in paired DD and WD components of DDLPS. Considering the relevance of TMM for LPS onset and progression, the activity of a telomeric G-quadruplex binder (RHPS4) was assessed in DDLPS patient-derived cell lines.
    RESULTS: Equitoxic concentrations of RHPS4 in DDLPS cells altered telomeric c-circle levels, induced DNA damage, and resulted in the accumulation of γ-H2AX-stained micronuclei. This evidence was paralleled by an RHPS4-mediated reduction of in vitro cell migration and induction of apoptosis/autophagy.
    CONCLUSIONS: Our findings support telomere as an intriguing therapeutic target in DDLPS and suggest G-quadruplex binders as innovative therapeutic agents.
    Keywords:  G-quadruplex; apoptosis; autophagy; dedifferentiated liposarcoma; micronuclei; soft tissue sarcoma; telomeres
  3. Front Genet. 2022 ;13 834445
      Here we describe the identification of genes and their encoded proteins that are expressed in advanced grade tumors by reconstruction of a sarcoma cancer testis gene 1b/a (catg1b/a) network. CTAG1B/A is an ortholog of the yeast/Drosophila transcription factor Pcc1p, and a member of the KEOPS transcription complex. It has been implicated in telomere maintenance and transcriptional regulation through association with chromatin remodeling factors and is only expressed during adult testis germ cell differentiation. Ctag1b/a is re-activated in synovial sarcomas and myxoid liposarcomas but not in differentiated liposarcomas. We mapped CTAG1B/A protein to sarcoma transcription pathways with gene set expression analysis (GSEA) and using independent samples, we immunohistochemically identified expression of at least two network neighbors, RANBP2, and TLE1, thus validating our approach. This work demonstrates that mapping unknown genes to functional pathways by network re-construction is a powerful tool that can be used to identify candidate oncoproteins.
    Keywords:  CtaG; GSEA; RanBP2; TLE1; network; sarcoma; transcription
  4. Mod Pathol. 2022 Jun 07.
      Myxoid pleomorphic liposarcoma (MPLPS) is a recently described and extremely rare subtype of liposarcoma with a predilection for the mediastinum. However, the genomic features of MPLPS remain poorly understood. We performed comprehensive genomic profiling of MPLPS in comparison with pleomorphic liposarcoma (PLPS) and myxoid/round cell liposarcoma (MRLPS). Of the 8 patients with MPLPS, 5 were female and 3 were male, with a median age of 32 years old (range 10-68). All except one were located in the mediastinum, with invasion of surrounding anatomic structures, including chest wall, pleura, spine, and large vessels. All cases showed an admixture of morphologies reminiscent of PLPS and MRLPS, including myxoid areas with plexiform vasculature admixed with uni- and/or multivacuolated pleomorphic lipoblasts. Less common features included well-differentiated liposarcoma-like areas, and in one case fascicular spindle cell sarcoma reminiscent of dedifferentiated LPS. Clinically, 4 experienced local recurrence, 4 had distant metastases and 5 died of disease. Compared to PLPS and MRLPS, patients with MPLPS had worse overall and progression-free survival. Recurrent TP53 mutations were present in all 8 MPLPS cases. In contrast, in PLPS, which also showed recurrent TP53 mutations (83%), RB1 and ATRX losses were more common. MRLPS was highly enriched in TERT promoter mutations (88%) and PI3K/AKT pathway mutations. Copy number profiling in MPLPS revealed multiple chromosomal gains with recurrent amplifications of chromosomes 1, 19 and 21. Importantly, allele-specific copy number analysis revealed widespread loss of heterozygosity (80% of the genome on average) in MPLPS, but not in PLPS or MRLPS. Our findings revealed genome-wide loss of heterozygosity co-existing with TP53 mutations as a characteristic genomic signature distinct from other liposarcoma subtypes, which supports the current classification of MPLPS as a stand-alone pathologic entity. These results further expand the clinicopathologic features of MPLPS, including older age, extra-mediastinal sites, and a highly aggressive outcome.
  5. Ecancermedicalscience. 2022 ;16 1363
      Introduction: Systemic treatment for metastatic soft tissue sarcoma (STS) results in modest activity in second and further lines. The aim of this study was to evaluate the efficacy of ifosfamide and etoposide (IE) as a salvage regimen for patients with metastatic STS.Methods: A retrospective, single centre study included patients with STS treated with IE from 2010 to 2018. The primary endpoint was progression-free survival (PFS). Secondary endpoints were toxicity, response rate (RR) and overall survival (OS). Survival was estimated by the Kaplan-Meier method and log-rank test used to compare the groups.
    Results: A total of 33 patients were identified, median age was 43 years, 60% were female, 12 had leiomyosarcoma. IE was used in second line in 51.5% and in >third line in 30.3% of patients. Median number of cycles was four and treatment discontinuation due to grade 3/4 toxicity occurred in 30.3%. The objective RR was 9% and the disease control rate was 60.6%. Median PFS was 4 months (95% CI, 2.1-5.9) and the median OS was 15 months (95% CI, 7.1-22.9). In the univariate analysis, smoking history, line of therapy and prior response to previous chemotherapy were prognostic factors for PFS.
    Conclusion: IE showed activity in previously treated STS, but with a non-negligible toxicity profile, worse than that with other available therapies. The use of the IE combination is not supported by our findings outside a clinical trial for soft part sarcomas.
    Keywords:  chemotherapy; prognosis; sarcoma; treatment