- Gensterblum-Miller, Elizabeth;
- Bhangale, Apurva;
- Majid, Dana;
- Pienkowski, Victor;
- Rydzanicz, Malgorzata;
- Janiszewska, Joanna;
- Kostrzewska-Poczekaj, Magdalena;
- Chang, Clifford;
- Brummel, Collin;
- Michmerhuizen, Nicole;
- Wang, Jiayu;
- Sandford, Erin;
- Tewari, Muneesh;
- Wierzbicka, Malgorzata;
- Birkeland, Andrew;
- McHugh, Jonathan;
- Spector, Matthew;
- Giefing, Maciej;
- Jarmuz-Szymczak, Malgorzata;
- Heft Neal, Molly;
- Brenner, J
Mucoepidermoid Carcinoma (MEC) is a common salivary malignant neoplasm. Approximately 60 % of MECs harbor translocations between CRTC1 or CRTC3 and MAML2, which are thought to drive disease pathogenesis. However, the precise structural mechanism driving this rearrangement remains uncharacterized. Here, we performed multi-omic and long read genomic sequencing, discovering a chain of alterations that created the CRTC1::MAML2 fusion, but also an unexpected MAML2 to MYBL1 rearrangement, suggesting that MYBL1 may play a larger role in salivary gland cancers than previously recognized. Furthermore, we discovered and validated recurrent TERT rearrangements and amplifications in MEC models. 5/5 MEC cell lines and 36/39 (92 %) primary MEC tumors harbored a TERT rearrangement or copy number amplification. Custom sequencing of the TERT locus confirmed translocation breakpoints in 13/33 (39 %) MECs, while exome sequencing confirmed frequent TERT amplifications. Critically, TERT knockdown in NCI-H292, a cell line with TERT promoter rearrangement, reduced clonogenic cell survival, supporting a critical role of this gene in MEC tumorigenesis. Overall, our data suggest that complex chromothripsis rearrangement mechanisms drive the formation of structural variation in CRTC1::MAML2 fusion positive and negative tumors and reveal highly recurrent structural variation driving TERT rearrangement in MEC.