A specific missense mutation in GTF2I occurs at high frequency in thymic epithelial tumors
Iacopo Petrini, Paul S Meltzer, In-Kyu Kim, Marco Lucchi, Kang-Seo Park, Gabriella Fontanini, James Gao, Paolo A Zucali, Fiorella Calabrese, Adolfo Favaretto, Federico Rea, Jaime Rodriguez-Canales, Robert L Walker, Marbin Pineda, Yuelin J Zhu, Christopher Lau, Keith J Killian, Sven Bilke, Donna Voeller, Sivanesan Dakshanamurthy, Yisong Wang, Giuseppe Giaccone, Iacopo Petrini, Paul S Meltzer, In-Kyu Kim, Marco Lucchi, Kang-Seo Park, Gabriella Fontanini, James Gao, Paolo A Zucali, Fiorella Calabrese, Adolfo Favaretto, Federico Rea, Jaime Rodriguez-Canales, Robert L Walker, Marbin Pineda, Yuelin J Zhu, Christopher Lau, Keith J Killian, Sven Bilke, Donna Voeller, Sivanesan Dakshanamurthy, Yisong Wang, Giuseppe Giaccone
Abstract
We analyzed 28 thymic epithelial tumors (TETs) using next-generation sequencing and identified a missense mutation (chromosome 7 c.74146970T>A) in GTF2I at high frequency in type A thymomas, a relatively indolent subtype. In a series of 274 TETs, we detected the GTF2I mutation in 82% of type A and 74% of type AB thymomas but rarely in the aggressive subtypes, where recurrent mutations of known cancer genes have been identified. Therefore, GTF2I mutation correlated with better survival. GTF2I β and δ isoforms were expressed in TETs, and both mutant isoforms were able to stimulate cell proliferation in vitro. Thymic carcinomas carried a higher number of mutations than thymomas (average of 43.5 and 18.4, respectively). Notably, we identified recurrent mutations of known cancer genes, including TP53, CYLD, CDKN2A, BAP1 and PBRM1, in thymic carcinomas. These findings will complement the diagnostic assessment of these tumors and also facilitate development of a molecular classification and assessment of prognosis and treatment strategies.
Conflict of interest statement
COMPETING FINANCIAL INTERESTS
The authors declare no competing financial interests.
Figures
Source: PubMed