gene relations, further studies are required to define their contribution to the development and/or maintenance of MLS tumors. Diagnosis Low-grade and intermediate-grade MLS tumors can be identified histologically by their classic morphology of distinctive chicken-wire vasculature scattered throughout a myxoid stroma. However, high-grade MLS tumors can be difficult to distinguish from other round cell neoplasms, particularly high grade MLS tumors that consist of diffuse cell and/or pure round cell morphology to such an extent as to obscure this classic vascular-myxoid pattern. Detection of a DDIT3 gene rearrangements with the FUS or EWSR1 gene by in situ hybridization or immunohistochemistry or the RNA fusion transcripts of these genes by real-time polymerase chain reactions confirms the diagnosis of high-grade as well as ambiguous cases of low-grade or intermediate-grade MLS tumors. Treatment and prognosis MLS has typically been treated by surgical resection but may require more radical interventions, e.g. limb amputation may be needed when a limb's neurovascular bundle is compromised. The post-surgical risk of recurrence within 3 years after surgery has been reported to be ~15% when not all tumor is removed and ~10% when tumor removal is complete. The addition of radiotherapy to surgical resection has improved the local control of MLS tumors and has been recommended to treat unresectable and recurrent MLS. However, further studies are needed to determine the value of radiotherapy in treating the various varieties of MLS. Chemotherapy regimens using ifosfamide, an anthracycline such as daunorubicin, dacarbazine, and/or trabectedin have been found useful: a phase III clinical trial showed progression-free survival times in MLS patients treated with trabectedin or dacarbazine to be 5.6 and 1.5 months, respectively. In 2015 the Food and Drug Administration approved trabectedin for use in unresectable and metastatic liposarcomas. Overall, the 10-year survival rate of MLS individuals has been 77%, a survival rate appreciably longer than other liposarcoma forms. Compared to low-risk MLS, high-risk MLS (risk defined by tumor round cell content and/or other unfavorable prognostic indicators) is associated with increased rates of metastasis and therefore a shorter survival time. Increased tumor size (≥ 10 cm) is strongly associated with a higher grade MLS and therefore a shorter survival time. Other factors that have been associated with unfavorable outcomes in MLS include presence of tumor necrosis, age >45 years, P53 gene overexpression, and male gender. The round cell form of myxoid liposarcomas also appears to have a relatively poor prognosis: in various retrospective