Fluorescence in situ hybridization for MDM2 gene amplification as a diagnostic tool in lipomatous neoplasms

摘要: Well-differentiated liposarcoma/atypical lipomatous tumor and dedifferentiated liposarcoma can be difficult to distinguish from benign neoplasms other high-grade sarcomas, respectively. Cytogenetics in these tumors has identified ring giant chromosomes composed of 12q13-15 amplicons including the MDM2 gene. Identifying amplification by fluorescence situ hybridization may prove an adjunctive tool diagnosis neoplasms. Dual color employing a laboratory-developed BAC label probe cocktail specific for (12q15) centromeric region chromosome 12 (Abbott Molecular, DesPlaines, IL) was performed on formalin-fixed paraffin-embedded tissue whole sections atypical (n=13), liposarcomas (n=14), (n=30), pleomorphic sarcoma, not otherwise specified (n=10), microarray containing variety sarcomas (n=63). An MDM2/chromosome ratio >or=2.0 considered amplified, 2 signals both probes <2.0 polysomic 12. Of well-differentiated liposarcomas, 100% showed MDM2. Chromosome polysomy noted 89% spindle cell/pleomorphic lipomas, while all angiolipomas lipomas were nonamplified eusomic. observed 40% small subset (3/63). is sensitive (both 100%) evaluating low-grade The specificity decreases as portion than liposarcomas. Importantly, none lesions amplified even cells areas with minimal cytologic atypia making valuable limited biopsy samples