Patients with cancer can relapse if a few malignant cells survive treatment. Researchers show that high-throughput gene sequencing can detect this minimal residual disease (MRD) with greater sensitivity than conventional methods.
Harlan Robins of the Fred Hutchinson Cancer Research Center in Seattle, Washington, studied 43 children with T-lineage acute lymphoblastic leukaemia/lymphoma, which affects white blood cells called T cells. The team sequenced a region of two genes encoding T-cell receptors before treatment and then looked for the cancer-specific sequences in cells sampled after chemotherapy. When the researchers compared sequencing with the conventional method, which looks for cells with particular surface molecules, they found that both techniques detected cancer cells in 12 patients after treatment. However, only sequencing, which can find one cancerous cell in 100,000, identified MRD in a further 10 patients.
The test could potentially be adapted to monitor other blood cancers.