Archival single cell sequencing reveals persistent subclones over years to decades of DCIS progression

We developed Arc-well, the first high-throughput method that can perform single cell DNA sequencing of thousands of cells from FFPE tissues. We validated our method by profiling 40,330 single cells from cell lines, a frozen tissue, and 27 FFPE samples from breast, lung, and prostate tumors stored for 3-31 years. Our data show that in DCIS with recurrent DCIS/IDC, the dormant subclones were often missed during the initial treatment, having implications for both the clinical diagnosis and treatment of the disease.