Long-read DNA sequencing finds cancer drivers missed by standard tests — and traces a child's tumour to gene therapy

Researchers at Michigan Medicine (University of Michigan) described two studies on 16 October 2026 showing what long-read nanopore sequencing can reveal that conventional short-read sequencing misses. Short-read methods read DNA in pieces of a few hundred letters; long-read methods read thousands to tens of thousands in one stretch, showing how mutations are arranged.

Study 1: hidden cancer drivers (Cancer Discovery)

• Among 768 patients with prostate, breast or ovarian cancer, the team found 46 tumours with signs of genomic instability that conventional sequencing could not explain. Long-read sequencing resolved 32 of them by finding hidden alterations or chemical changes in genes that protect against cancer.
• In a broader screen of 4,496 tumour samples from 3,688 patients, they used long reads in selected cases to see how mutations were arranged in genes including NOTCH1, PDGFRB, KIT and PIK3CA — which can matter for drug resistance.
• In one woman with a strong family history of breast and ovarian cancer who had tested negative on a commercial gene panel, long-read sequencing of blood found a disease-causing insertion in BRCA2.

Study 2: a tumour after gene therapy (NEJM)

• A 3-year-old boy with Krabbe disease, a rare inherited nerve disorder, received an AAV-based gene therapy delivering a working GALC gene in a clinical trial, after a stem-cell transplant.
• 26 months later, routine imaging showed a small tumour beside his spine. Sequencing found that a fragment of the modified AAV had inserted into the GLI1 gene, driving unusually high activity of a gene that can promote tumour growth.
• At the time of the report the child had no tumour-related symptoms or neurological deficits and was being monitored with imaging.

Limitations

• The NEJM paper is a single-patient report: it shows that such an event can happen, not how often. Senior author Arul Chinnaiyan stressed that “gene therapy holds great promise” and called for long-term monitoring.
• The Cancer Discovery results come from one centre’s sequencing programme and selected cases; whether long-read testing improves patient outcomes or is cost-effective in routine care was not shown.
• This summary is based on the university’s release and the paper titles; we did not review the full papers.

Questions about genetic testing or gene therapy are best discussed with your doctor or a genetic counsellor.