Johnson, Kevin C.

Abstract Next-generation sequencing has transformed cancer care by providing essential insights for diagnosis, prognosis, and treatment. However, variability in testing timing, reporting practices, and interpretation challenges limits its clinical impact. This article highlights key opportunities to optimize somatic reporting, emphasizing the importance of timely testing throughout the cancer care continuum to maximize the diagnostic and therapeutic relevance of findings. Technical factors such as test design, sequencing depth, and the use of liquid biopsy substantially influence result accuracy and interpretation, underscoring the need for careful integration with clinical history. Standardized reporting practices that clearly delineate diagnostic, prognostic, and therapeutic findings can enhance the clinical utility of next-generation sequencing results. Streamlined formats and curated clinical trial data further support actionable decision making. Additionally, direct patient engagement and education are essential for empowering patients to navigate genomic testing and make informed decisions about their care. By leveraging multidisciplinary tumor boards, decision-support tools, and emerging artificial intelligence technologies, clinicians can better navigate the complexities of somatic reports. Standardization and clarity in reporting are critical to advancing precision oncology, empowering providers and patients to make informed treatment decisions and improve outcomes.

Abstract Oligodendroglioma is characterized by oligodendrocyte-like histology, mutation in the IDH genes, along with codeletion of chromosome arms 1p and 19q. Treatment for oligodendrogliomas combines surgery, followed by observation, and chemotherapy and/or radiotherapy when tumors progress. Most oligodendrogliomas eventually recur with a more aggressive phenotype, leading to patient mortality but molecular mechanisms remain poorly understood. To investigate the molecular trajectory of oligodendroglioma, we collected more than 270 longitudinal samples from over 130 oligodendroglioma patients, to perform whole genome or whole exome sequencing, bulk RNA, and single-nucleus RNA sequencing (n = 30 samples). Common mutations in IDH1/2, TERT promoter, CIC, and FUBP1 were observed. About half of the CIC and FUBP1 mutations occurred in the initial sample and persisted stably throughout recurrence. The majority of PIK3CA and PIK3R1 mutations were either shared or present in recurrences only implicating the PI3K pathway in oligodendroglioma recurrence. Mutational signature analysis revealed 34.5% of tumors treated with alkylating agents acquired SBS11/SBS31 associated hypermutation. By integrating signatures with clonality estimates, we approximated the timing of mutational processes and found that clonal timings of treatment related mutations correlate with the treatment administration date. We found that aging signature-related mutations were mostly clonal, and treatment signature-related mutations were more likely to be sub-clonal, supporting the late emergence of these mutations following treatment. We observed increased somatic copy number alterations in oligodendroglioma recurrences, reflected in notable chromosome 4 losses. Associating treatment with snRNAseq derived cellular states, we observed a significant increase in the fraction of proliferating stem-like cells in the hypermutator versus non-hypermutator recurrent samples. These findings shed light on the molecular changes occurring in oligodendrogliomas following treatment and provide insights that may aid in targeting treatment resistance.