Oncogenesis and classification of mixed-type liposarcoma: a radiological, histopathological and molecular biological analysis

HER3 (ERBB3) amplification in liposarcoma - a putative new therapeutic target?

BACKGROUND

Liposarcomas are among the most common mesenchymal malignancies. However, the therapeutic options are still very limited and so far, targeted therapies had not yet been established. Immunotherapy, which has been a breakthrough in other oncological entities, seems to have no efficacy in liposarcoma. Complicating matters further, classification remains difficult due to the diversity of morphologies and nonspecific or absent markers in immunohistochemistry, leaving molecular pathology using FISH or sequencing as best options. Many liposarcomas harbor MDM2 gene amplifications. In close relation to the gene locus of MDM2, HER3 (ERBB3) gene is present and co-amplification could occur. Since the group of HER/EGFR receptor tyrosine kinases and its inhibitors/antibodies play a role in a broad spectrum of oncological diseases and treatments, and some HER3 inhibitors/antibodies are already under clinical investigation, we hypothesized that in case of HER3 co-amplifications a tumor might bear a further potential therapeutic target.

METHODS

We performed FISH analysis (MDM2, DDIT3, HER3) in 56 archived cases and subsequently performed reclassification to confirm the diagnosis of liposarcoma.

RESULTS

Next to 16 out of 56 cases needed to be re-classified, in 20 out of 54 cases, a cluster-amplification of HER3 could be detected, significantly correlating with MDM2 amplification. Our study shows that the entity of liposarcomas show specific molecular characteristics leading to reclassify archived cases by modern, established methodologies. Additionally, in 57.1% of these cases, HER3 was cluster-amplified profusely, presenting a putative therapeutic target for targeted therapy.

CONCLUSION

Our study serves as the initial basis for further investigation of the HER3 gene as a putative therapeutic target in liposarcoma.

Epidemiology and survival of liposarcoma and its subtypes: A dual database analysis

PURPOSE

Liposarcoma (LPS) is a one of the most commonly diagnosed soft tissue sarcomas. Little is known about the epidemiology and prognosis of each subtype. We present an analysis of epidemiology and survival of the subtypes of LPS using a national database.

METHODS

We queried the Survival Epidemiology, and End Results (SEER) and the Canadian Institute for Clinical Evaluative Sciences (ICES) databases for data on 7 types of LPS. Pearson's chi square was used to determine associations between variables and subtypes. Kaplan-Meier and Cox Regression analyses were performed for two tests: one using SEER data and the other using variables common to both SEER and ICES.

RESULTS

The well-differentiated subtype was the most common subtype identified. Metastatic disease was associated with decreased survival across all subtypes and age >35 was associated with decreased survival in well-differentiated and myxoid subtypes. Tumor grade was associated with decreased survival in the well-differentiated, myxoid, mixed, and round cell subtypes. In the secondary analysis, age >35 was associated with decreased survival in the myxoid subtype.

CONCLUSIONS

The prognosis of liposarcoma differs greatly by subtype. Clinicians should account for patient factors at the time of diagnosis to best navigate treatment of their patients.

Patient With Slow-Growing Mediastinal Mass Presents With Chest Pain and Dyspnea

A 52-year-old white woman presented with severe pain over the right upper abdomen and nonpleuritic, right-sided, lower chest-wall pain. Her pain had progressively gotten more frequent and severe over the last 5 months. It was also associated with a nonexertional, pressure-like sensation in the central chest. The patient denied any shortness of breath, fevers, cough, or any sputum production. She was taking levothyroxine for hypothyroidism and was a 30-pack-year current smoker; there was no history of drug abuse or occupational exposure. Previous chest radiographs dating back to 5 years consistently showed an elevated right-sided hemidiaphragm without any infiltrates or effusions; cardiomediastinal structures were unremarkable. She had not had a previous workup for these abnormal findings.

Extensive lipoma-like changes of myxoid liposarcoma: morphologic, immunohistochemical, and molecular cytogenetic analyses

Myxoid liposarcomas (MLSs) with extensive lipoma-like changes (MLSLC) are rare, and it is often difficult to distinguish them from well-differentiated liposarcoma (LS)/dedifferentiated LS (WDLS/DDLS) with myxoid changes. For the characterization of these neoplasms, we studied 8 MLSLCs, 11 ordinary MLSs, 4 WDLSs, and 6 DDLSs. Cytogenetically, MLSLC and ordinary MLS were characterized by t(12;16)(q13;p11) and FUS-DDIT3 fusion gene, whereas WDLS/DDLS lacked the fusion gene but possessed giant marker/ring chromosomes. Both lipoma-like and myxoid components of the same MLSLC exhibited the identical FUS-DDIT3, as confirmed by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR). Immunohistochemically, MDM2 and CDK4 were positive in WDLS/DDLS but negative in MLSLC and ordinary MLS. PPARγ, C/EBPα, adipophilin, and perilipin were found in each type of LS. Adipophilin was expressed chiefly in tiny fat droplets of immature lipoblasts, whereas perilipin showed a strong positive staining in large fat vacuoles of signet ring and multivacuolated lipoblasts. The Ki-67 labeling index was lower in the lipoma-like component of MLSLC when compared with the myxoid component of the same tumors as well as ordinary MLS (p < 0.001). When compared with ordinary MLS, MLSLC may be less aggressive in clinical behavior (rare recurrences or metastases) after a wide surgical excision. In conclusion, the distinction between MLSLC and WDLS/DDLS is important, because of the differences of molecular cytogenetic features as well as clinical behaviors between these distinct sarcomas presenting similar morphologic features. In addition, the combined immunohistochemical detection of adipophilin and perilipin may provide a useful ancillary tool for identification of lipoblastic cells in soft tissue sarcomas.

Myxoid/round cell liposarcoma of the supraclavicular fossa

Metastases from the tracheobronchial tree and the genitourinary and gastrointestinal systems are the most common malignant lesions of the supraclavicular fossa. Liposarcomas in this region, as primary tumors, are rarely encountered. In this article, we report a case of myxoid liposarcoma of the supraclavicular fossa with a fulminant course.

Surgical experience with retroperitoneal liposarcoma in a single korean tertiary medical center

Purpose

This is a report of the surgical treatment and prognosis of retroperitoneal liposarcoma (RPLS) in Koreans.

Materials and Methods

Nineteen patients treated for RPLS between July 1, 1984, and March 31, 2009, were included. Patient demographics, histopathologic subtypes, survival rate, disease recurrence rate and interval, and adjuvant therapy were reviewed and analyzed.

Results

Of the 19 patients diagnosed with RPLS, 26.3% presented with well-differentiated RPLS, 10.5% with dedifferentiated RPLS, 15.8% with myxoid/round cell type, and 47.4% with mixed-type liposarcoma. The mean follow-up period was 66.8 months (range, 6 to 165 months). Primary RPLS was treated in 17 patients. Nine patients (52.9%) had recurrent disease, and recurrence developed at a mean of 47.7 months after primary or repeated surgical treatment. The overall survival rate was 84.2% during a mean follow-up of 66.8 months. The 3- and 5-year survival rates were 86.9%, and the 10-year survival rate was 69.5%. The recurrence interval was significantly shorter in recurrent RPLS cases (p=0.023). The mean growth rate of locally recurrent tumors was 0.34 cm per month.

Conclusions

The survival rates reported here were higher than in previous studies. Locally recurrent tumors presented with a low growth rate, which may have contributed to the relatively high survival rate. A high prevalence of mixed-type RPLS was also noted, and its cause and prognosis require further research.

Variation in myxoid liposarcoma: Clinicopathological examination of four cases with detectable TLS-CHOP or EWS-CHOP fusion transcripts whose histopathological diagnosis was other than myxoid liposarcoma

Liposarcomas are separated into clinicopathological entities by a characteristic morphological spectrum and distinctive genetic changes. Myxoid liposarcoma (MLS) represents one such entity with specific chromosomal translocations leading to the generation of fusion genes, the human translocation liposarcoma (TLS)-CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP) or the Ewing sarcoma (EWS)-CHOP. In the present study, four cases of liposarcoma with detection of TLS-CHOP or EWS-CHOP, whose postoperative diagnosis was other than MLS (one well-differentiated liposarcoma, two de-differentiated liposarcomas and one unclassified) were examined for medical records, imaging data and histopathology. Clinical records demonstrated that three of the four cases were considerably difficult to diagnose definitively, and histopathological re-examination pointed out areas of myxomatous change as a minor component (<10%). Their dominant components (>90%) resembled pleomorphic sarcoma, pleomorphic malignant fibrous histiocytoma and monophasic synovial sarcoma. The current cases may represent an extreme variant of the morphological spectrum within MLS. In cases of difficulty in making definitive diagnosis of soft tissue sarcoma by standard histopathological examination and identification of myxoid stroma even as a minor component, analyzing TLS-CHOP and EWS-CHOP fusion genes may aid the diagnosis of unusual MLS.

Large retroperitoneal liposarcoma - a series of five cases

Large retroperitoneal liposarcomas represent a unique situation and require a more aggressive surgical approach, including multiple resections for recurrences. We report a series of 5 cases of large retroperitoneal liposarcoma managed aggressively with surgical resection. All cases presented with lump and abdominal pain and diagnosis was established by Ultrasonography and CT scan. Post-operative course was uneventful and a median follow up of 3 years, all patients were free from recurrence.

Contributions of cytogenetics and molecular cytogenetics to the diagnosis of adipocytic tumors

Over the last 20 years, a number of tumor-specific chromosomal translocations and associated fusion genes have been identified for mesenchymal neoplasms including adipocytic tumors. The addition of molecular cytogenetic techniques, especially fluorescence in situ hybridization (FISH), has further enhanced the sensitivity and accuracy of detecting nonrandom chromosomal translocations and/or other rearrangements in adipocytic tumors. Indeed, most resent molecular cytogenetic analysis has demonstrated a translocation t(11;16)(q13;p13) that produces a C11orf95-MKL2 fusion gene in chondroid lipoma. Additionally, it is well recognized that supernumerary ring and/or giant rod chromosomes are characteristic for atypical lipomatous tumor/well-differentiated liposarcoma and dedifferentiated liposarcoma, and amplification of 12q13–15 involving the MDM2, CDK4, and CPM genes is shown by FISH in these tumors. Moreover, myxoid/round cell liposarcoma is characterized by a translocation t(12;16)(q13;p11) that fuses the DDIT3 and FUS genes. This paper provides an overview of the role of conventional cytogenetics and molecular cytogenetics in the diagnosis of adipocytic tumors.