PolyG-DS: An ultrasensitive polyguanine tract–profiling method to detect clonal expansions and trace cell lineage

Significance The ability to detect precancerous clones and reconstruct cancer evolution is important for early cancer detection and improving prevention and treatment strategies. We present PolyG-DS, a sequencing method that combines the unique properties of polyguanine tracts (PolyGs) for cell lineage tracing with ultrahighaccuracy duplex sequencing (DS). PolyG-DS enables accurate and reproducible PolyG genotyping, providing high sensitivity for the detection of low-frequency alleles in mixed populations. This translates into an improved ability to identify clonal expansions within normal tissue, with potential application to detect cancer progression in preneoplastic diseases such as ulcerative colitis. Because PolyG-DS is driver mutation agnostic, it provides a universal, cost-effective approach for assessing tumor evolution across cancer types.