Systematic analysis of telomere length and somatic alterations in 31 cancer types

Abstract

Cancer cells survive cellular crisis through telomere maintenance mechanisms. We report telomere lengths in 18,430 samples, including tumors and non-neoplastic samples, across 31 cancer types. Tumor telomeres were shorter compared to normal tissues, and longer in sarcomas and gliomas compared to other cancers. Amongst 6,835 cancers, 73% expressed telomerase reverse transcriptase ( TERT), which was associated with TERT point mutations, rearrangements, DNA amplifications, and transcript fusions, and predicted telomerase activity. TERT promoter methylation provided an additional deregulatory TERT expression mechanism. Five percent of cases, mostly with undetectable TERT, harbored ATRX or DAXX alterations, demonstrated elongated telomeres and increased telomeric repeat containing RNA ( TERRA). The remaining 22% of tumors neither expressed TERT, nor harbored alterations in ATRX/DAXX. In this group, telomere length positively correlated with TP53 and RB1 mutations. Our analysis integrates TERT abnormalities, telomerase activity and genomic alterations with telomere length in cancer.