Clinical Application of Chromosome Microarray Analysis in the Diagnosis of Lipomatous Tumors.

Well-differentiated liposarcoma/atypical lipomatous tumor (WDLS/ALT) and dedifferentiated liposarcoma (DDLS) have characteristic supernumerary ring and giant marker chromosomes involving the chromosomal region 12q13-15 which contains MDM2 (12q15), CDK4 (12q14.1), HMGA2 (12q14.3), YEATS4 (12q15), CPM (12q15), and FRS2 (12q15). Detecting MDM2 amplification by fluorescence in situ hybridization (FISH) is considered to be the gold standard for the diagnosis of WDLS/ALT and DDLS. In this study, formalin fixed paraffin embedded clinical specimens (16 liposarcomas and 19 benign lipomatous tumors) were used to detect MDM2 amplification and other chromosomal alterations in WDLS/ALT and DDLS by single nucleotide polymorphism-based chromosome microarray (CMA). All 16 liposarcomas showed MDM2 amplification with a MDM2/cep12 ratio from 2.4 to 8.4 by CMA. Ten (62.5%) of these cases had CDK4/cep12 ratio ≥2.0. All the cases without CDK4 amplification were from the thigh. The MDM2/cep12 ratio of all the benign lipomatous tumors (19/19) was within the normal limits. Twenty-one of the 35 benign lipomatous tumors and liposarcomas were also tested for MDM2 amplification by FISH. All the FISH results were consistent with the CMA results (100%). Along with MDM2 amplification, all 16 liposarcomas (100%) also showed amplification of YEATS4, CPM and FRS2. Only 11 of 16 (69%) cases showed HMGA2 amplification. In conclusion, this study demonstrated that CMA on routine formalin fixed paraffin embedded tissue is a sensitive and specific clinical test for detection of MDM2 gene amplification. Moreover, CMA allows simultaneous detection of genomic changes of interest including CDK4 and others, which provides enriched information for diagnosing lipomatous tumors.

Lipophyllodes of the breast. A reappraisal of fat-rich tumors of the breast based on 22 cases integrated by immunohistochemical study, molecular pathology insights, and clinical follow-up.

We have studied 22 cases of mammary lipophyllodes tumors (LPT), analyzing their clinicopathologic features along with available follow-up. All cases were tested for cytokeratins, S100 protein, and MDM2, and in selected cases for estrogen receptor, smooth muscle actin, bcl2, desmin, and myogenin. Patients were women aged 21 to 69 years (average, 45 years), and LPT size ranged from 1.6 to 30 cm (average, 9.7 cm). Microscopically, LPT segregated as follows: atypical lipoma-like tumor/well-differentiated liposarcoma (ALT/WDL), 8 cases; myxoid, 6; and pleomorphic/poorly differentiated/round cell, 8, including a case of dedifferentiated liposarcoma. Immunohistochemistry studies showed focal positive staining for S100 and CD34 in most ALT/WDL, and desmin and myogenin in 2 cases with evidence of rhabdomyoblastic differentiation. MDM2 positivity was focally seen in 1 case. Follow-up was available in 8 cases. Multiple recurrent tumors were seen in 2 patients, and metastatic disease to the lung was seen in 2 patients. In 4 patients with a follow-up between 2 and 15 years there was no evidence of recurrent or metastatic disease. Patients with ALT/WDL (2/2) were alive with no evidence of disease; 2 of 4 patients with myxoid liposarcoma component experienced tumor recurrence, whereas pleomorphic liposarcoma LPT pursued a less favorable course although only 1 patient died of the condition. Absence of MDM2 reactivity in most cases seems not as meaningful as in fatty tumors of somatic soft parts.

Prognostic factors and expression of MDM2 in patients with primary extremity liposarcoma.

OBJECTIVE: The objective of this study was to investigate MDM2 (murine double minute 2) protein expression and evaluate its relationship with some anatomical and pathological aspects, aiming also to identify prognostic factors concerning local recurrence-free survival, metastasis-free survival and overall survival in patients with primary liposarcomas of the extremities. MATERIALS AND METHODS: Of 50 patients with primary liposarcomas of the extremities admitted to a Reference Service, between 1968 and 2004, 25 were enrolled in the study, following eligibility and exclusion criteria. RESULTS: The adverse factors that influenced the risk for local recurrence in the univariant analysis included male sex (P = 0.023), pleomorphic histological subtype (P = 0.027), and high histological grade (P = 0.007). Concerning metastasis-free survival, age less than 50 years (P = 0.040), male sex (P = 0.040), pleomorphic subtype (P < 0.001), and high histological grade (P = 0.003) had a worse prognosis. Adverse factors for overall survival were age under 50 years (P = 0.040), male sex (P = 0.040), pleomorphic subtype (P < 0.001), and high histological grade (P = 0.003). CONCLUSIONS: There was no correlation between immunohistochemically observed MDM2 protein expressions and the anatomical and pathological variables studied. The immunohistochemical expression of MDM2 protein was not considered to have a prognostic value for any of the surviving patients in this study (local recurrence-free survival, metastasis-free survival, or overall survival). The immunoexpression of MDM2 protein was a frequent event in the different subtypes of liposarcomas.

Prognostic factors and expression of MDM2 in patients with primary extremity liposarcoma

OBJECTIVE: The objective of this study was to investigate MDM2 (murine double minute 2) protein expression and evaluate its relationship with some anatomical and pathological aspects, aiming also to identify prognostic factors concerning local recurrence-free survival, metastasis-free survival and overall survival in patients with primary liposarcomas of the extremities. MATERIALS AND METHODS: Of 50 patients with primary liposarcomas of the extremities admitted to a Reference Service, between 1968 and 2004, 25 were enrolled in the study, following eligibility and exclusion criteria. RESULTS: The adverse factors that influenced the risk for local recurrence in the univariant analysis included male sex (P = 0.023), pleomorphic histological subtype (P = 0.027), and high histological grade (P = 0.007). Concerning metastasis-free survival, age less than 50 years (P = 0.040), male sex (P = 0.040), pleomorphic subtype (P < 0.001), and high histological grade (P = 0.003) had a worse prognosis. Adverse factors for overall survival were age under 50 years (P = 0.040), male sex (P = 0.040), pleomorphic subtype (P < 0.001), and high histological grade (P = 0.003). CONCLUSIONS: There was no correlation between immunohistochemically observed MDM2 protein expressions and the anatomical and pathological variables studied. The immunohistochemical expression of MDM2 protein was not considered to have a prognostic value for any of the surviving patients in this study (local recurrence-free survival, metastasis-free survival, or overall survival). The immunoexpression of MDM2 protein was a frequent event in the different subtypes of liposarcomas.

Ether à go-go potassium channel expression in soft tissue sarcoma patients.

BACKGROUND: The expression of the human Eag1 potassium channel (Kv10.1) is normally restricted to the adult brain, but it has been detected in both tumour cell lines and primary tumours. Our purpose was to determine the frequency of expression of Eag1 in soft tissue sarcoma and its potential clinical implications. RESULTS: We used specific monoclonal antibodies to determine the expression levels of Eag1 in soft tissue sarcomas from 210 patients by immunohistochemistry. Eag1 was expressed in 71% of all tumours, with frequencies ranging from 56% (liposarcoma) to 82% (rhabdomyosarcoma). We detected differences in expression levels depending on the histological type, but no association was seen between expression of this protein and sex, age, grade or tumour size. Four cell lines derived from relevant sarcoma histological types (fibrosarcoma and rhabdomyosarcoma) were tested for Eag1 expression by real-time RT-PCR. We found all four lines to be positive for Eag1. In these cell lines, blockage of Eag1 by RNA interference led to a decrease in proliferation. CONCLUSION: Eag1 is aberrantly expressed in over 70% sarcomas. In sarcoma cell lines, inhibition of Eag1 expression and/or function leads to reduced proliferation. The high frequency of expression of Eag1 in primary tumours and the restriction of normal expression of the channel to the brain, suggests the application of this protein for diagnostic or therapeutic purposes.