Amplification of the STOML3, FREM2, and LHFP genes is associated with mesenchymal differentiation in gliosarcoma

Masaya Nagaishi, Young Ho Kim, Michel Mittelbronn, Felice Giangaspero, Werner Paulus, Benjamin Brokinkel, Anne Vital, Yuko Tanaka, Yoichi Nakazato, Catherine Legras-Lachuer, Joel Lachuer, Hiroko Ohgaki*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

29 Citations (Scopus)


Gliosarcoma is a rare glioblastoma variant characterized by a biphasic tissue pattern with alternating areas that display either glial (glial fibrillary acidic protein-positive) or mesenchymal (reticulin-positive) differentiation. Previous analyses have shown identical genetic alterations in glial and mesenchymal tumor areas, suggesting that gliosarcomas are genetically monoclonal, and mesenchymal differentiation was considered to reflect the elevated genomic instability of glioblastomas. In the present study, we compared genome-wide chromosomal imbalances using array comparative genomic hybridization in glial and mesenchymal tumor areas of 13 gliosarcomas. The patterns of gain and loss were similar, except that the gain at 13q13.3-q14.1 (log 2 ratio >3.0), containing the STOML3, FREM2, and LHFP genes, which was restricted to the mesenchymal tumor area of a gliosarcoma. Further analyses of 64 cases of gliosarcoma using quantitative PCR showed amplification of the STOML3, FREM2, and LHFP genes in 14 (22%), 10 (16%), and 7 (11%) mesenchymal tumor areas, respectively, but not in glial tumor areas. Results of IHC analysis confirmed that overexpression of STOML3 and FREM2 was more extensive in mesenchymal than in glial tumor areas. These results suggest that the mesenchymal components in a small fraction of gliosarcomas may be derived from glial cells with additional genetic alterations.

Original languageEnglish
Pages (from-to)1816-1823
Number of pages8
JournalAmerican Journal of Pathology
Issue number5
Publication statusPublished - May 2012
Externally publishedYes


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