Telomere Maintenance Is Acquired at Liposarcoma Dedifferentiation, and Genetically Longer Telomeres Are Associated With Liposarcoma Risk
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PURPOSE
The impact of telomere length, telomerase gene alterations and alternative lengthening of the telomere in sarcoma subtypes remains unclear.
METHODS
We have analyzed 11,792 patients with sarcoma next-generation sequencing performed across 19 centers in AACR Project GENIE v20.0. Telomerase activation was defined as TERT promoter mutation, amplification, or rearrangement, and ATRX/DAXX inactivation served as the ALT proxy. Findings were tested for TERT expression in The Cancer Genome Atlas (TCGA), for overall survival (OS) in MSK-IMPACT 50K, and for replication in an independent Foundation Medicine cohort. Mendelian randomization (MR) in FinnGen tested germline telomere length.
RESULTS
Telomerase activation (8.8%) and ATRX/DAXX loss (8.0%) were mutually exclusive across subtypes (odds ratio [OR], 0.52; 95% CI, 0.29 to 0.92) and segregated by histology. In MDM2 -amplified dedifferentiated liposarcoma (DDLPS), telomerase was activated through TERT amplification (17.2%) or rearrangement (2.7%), never promoter mutation (0/261), and never with ATRX/DAXX loss (0/49; P = .011). TERT -amplified tumors expressed TERT (TCGA; P = .002), and amplification was largely focal. Telomere maintenance alterations were present in 28.0% of DDLPS versus 8.7% of well-differentiated liposarcoma ( P < .001) and predicted shorter OS in DDLPS (hazard ratio, 2.04; 95% CI, 1.23 to 3.39; P = .005). ATRX/DAXX loss was more frequent in uterine than extrauterine leiomyosarcoma in GENIE (adjusted OR, 1.96) and in the independent cohort (OR, 1.95; both P < .001). Genetically longer telomeres were associated with liposarcoma (OR per SD, 4.10; 95% CI, 2.15 to 7.81).
CONCLUSION
Sarcoma telomere maintenance is histology-specific, telomerase activation and ALT are mutually exclusive. In liposarcoma it is acquired at dedifferentiation through focal TERT amplification or ALT and identifies DDLPS with inferior survival. Long telomere was associated with elevated risk of liposarcoma genetically.
