Distinct MDM2 and P14ARF expression and centrosome amplification in well-differentiated liposarcomas

• Published in: Genes chromosomes & cancer Vol. 39; no. 2; pp. 99 - 109
• Main Authors: Perucca-Lostanlen, D., Rostagno, P., Grosgeorge, J., Marcié, S., Gaudray, P., Turc-Carel, C.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-02-2004
• Subjects: Adult; Aged; Aged, 80 and over; Centrosome - chemistry; Centrosome - metabolism; Centrosome - pathology; Chromosome Aberrations; Gene Amplification - genetics; Gene Expression Profiling - methods; Gene Expression Regulation, Neoplastic - genetics; Humans; Karyotyping; Lipoma - genetics; Lipoma - pathology; Liposarcoma - classification; Liposarcoma - genetics; Liposarcoma - pathology; MDM2 protein; Middle Aged; Mitosis - genetics; Nuclear Proteins; P14ARF protein; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins c-mdm2; Retroperitoneal Neoplasms - genetics; Retroperitoneal Neoplasms - pathology; Soft Tissue Neoplasms - classification; Soft Tissue Neoplasms - genetics; Soft Tissue Neoplasms - pathology; Spindle Apparatus - genetics; Spindle Apparatus - metabolism; Tumor Cells, Cultured; Tumor Suppressor Protein p14ARF - genetics; Tumor Suppressor Protein p53 - genetics
• ISSN: 1045-2257; 1098-2264
• DOI: 10.1002/gcc.10303

Well‐differentiated liposarcomas (WDLs) are common soft‐tissue tumors in adults. They are characterized by large marker chromosomes and/or ring chromosomes containing 12q‐derived sequences in which MDM2 is consistently amplified. WDLs are subdivided into two subtypes according to their karyotype. Type D cells exhibit a near‐diploid karyotype, with very few or no chromosome changes. Type H cells exhibit a near‐tetraploid karyotype and many structural changes. Expression of P14ARF, MDM2, and TP53 proteins was assayed in the two WDL subtypes to establish whether distinct expression profiles correlated with cell ploidy. Although a transcriptionally functional TP53 was present in most tumors independent of their karyotype, type H cells were characterized by high levels of P14ARF and MDM2 proteins. Although amplified within similar chromosome markers in type D tumors, MDM2 did not appear to be overexpressed. In addition, it was present as a C‐terminal truncated protein, indicative of alternatively spliced variants of MDM2 mRNA. As the existence of karyotypically distinct tumors could result from alterations of the mitotic machinery, we investigated the centrosome behavior in the two WDL subtypes. Centrosome amplification occurred in WDL tumors types H and D independent of their ploidy status. Moreover, no functional centrosome difference was found between the two tumor subtypes. © 2003 Wiley‐Liss, Inc.