Abstract 4341: Non canonical mitochondrial hotspot mutations in cancer

Abstract

Abstract The vast majority of recurrent somatic mutations arising in tumors affect protein-coding genes in the nuclear genome. Here, through population-scale analysis of 15,619 whole tumor genomes, we report the discovery of highly recurrent mutations affecting both the small (12S, MT - RNR1) and large (16S, MT - RNR2) RNA subunits of the mitoribosome. In total, we identified 70 recurrent, hotspot mutations affecting either subunit of the mitoribosome. Compared to non-hotspot positions, rRNA hotspots preferentially affect positions participating in Watson-Crick base pairing, and tend to arise at positions under strong purifying selection in the germline. Consistent with their putative selection, hotspot rRNA alleles arose at higher heteroplasmy than silent mutations under neutral selection. Transcriptional and metabolomic profiling of the m.1227G>A MT - RNR1 hotspot revealed a heteroplasmic dosage-dependent shift in energy generation towards glycolysis. Mutations disrupting the mitoribosome therefore represent a novel class of functional mutations under positive selection in cancer genomes. Citation Format: Sonia Boscenco, Jaqueline Tait-Mulder, Minsoo Kim, Cerise Tang, Mark Zucker, Tricia Park, Wei Wei, Patrick F. Chinnery, Payam A. Gammage, Ed Reznik. Non canonical mitochondrial hotspot mutations in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4341.