Myxoid/Round Cell Liposarcoma

The type 1 TLS/CHOP chimeric transcript is a result of the above-mentioned t(12 16) and is a very sensitive and specific molecular alteration for the myxoid/round cell liposarcoma entityOikawa and colleagues have developed a monoclonal antibody to this fusion transcript, which they claim is highly specific and sensitive with formalin-fixed paraffin-embedded tissue. However, there is no literature on its use. As a diagnostic tool, this is a good example of a genomic application of me. 

De Vreeze RS, de Jong D, Tielen IH, et al. Primary retroperitoneal myxoid/round cell liposarcoma is a nonexisting disease An immunohistochemical and molecular biological analysis. Mod Pathol. 2008 E-pub. 

Oda Y, Yamamoto H, Takahiira T, et al. Frequent alteration of pl6 (INK4a/pl4 (ARE) and p53 pathways in the round cell component of myxoid/round cell liposarcoma p53 gene alterations and reduced pl4 (ARE) expression both correlate with poor prognosis./ Pathol. 2005 207 410-421. 

NCT00579501 Safety and Efficacy Study of Trabectedin for the Treatment of Localized Myxoid / Round Cell Liposarcoma... 

Table VII Genomics of Myxoid/Round Cell Liposarcoma (MyLSrc)...

Demicco EG, Tiorres KE, Ghadimi MP, Colombo C, Bolshakov S, Hoffman A, Peng T, Bov6e IV, Wang WL, Lev D, Lazar AJ. Involvement of the PI3K/Akt pathway in myxoid/round cell liposarcoma. Mol Pathol. 2012 25 212-21. 

Hisaoka M, Tsuji S, Morimitsu Y, et al. Detection of TLS/FUS-CHOP fusion transcripts in myxoid and round cell liposarcomas by nested reverse RT-PCR using archival paraffin embedded tissue. J Diagn Mol Pathol. 1998 7 96-101. 

Oikawa K, Ishida T, Imamura T, et al. Generation of the novel monoclonal antibody against TLS/EWS-CHOP chimeric oncoproteins that is applicable to one of the most sensitive assays for myxoid and round cell liposarcomas. Am J Surg Pathol. 2006 30 351-356. 

The t(12 16)(ql3 pll) translocation is the most common translocation, described in more than 90% of myxoid and round cell liposarcoma, mainly those arising within the thigh soft tissue. Myxoid liposarcoma arising elsewhere seems to be not related to this specific genetic abnormality. The t(12 16)(ql3 pll) translocation is caused by the fusion of the TLS gene and the CHOP gene. 

As the two above-described translocations are specific for myxoid and round cell liposarcoma, they can be used as sensitive molecular markers to distinguish both liposarcoma types from other neoplastic or nonneoplastic lesions with similar morphologic features. This method can be also used for the examination of surgical margins after surgical resection or for the detection of micrometastases. Additionally,... 

Liposarcoma is easily recognized by most pathologists in its prototypical differentiated forms. Nevertheless, myxoid and round cell variants of this neoplasm often contain few if any discernible lipoblasts and may therefore be difficult to identify. 

Some studies show that there is no significant association between the fusion variant and the tumor behavior but other studies reported that the poorly differentiated round cell type of myxoid liposarcoma is mainly associated with the fusion transcript type 1. 

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