Polyguanine profiling and genotype analysis.

Primer sequences and a detailed PCR protocol for amplification of polyguanine markers can be found in Naxerova et al.¹⁰. We designed and validated several new markers for this study; their primer sequences can be found in Supplementary Table 7. Similarly, a very detailed description of the data analysis pipeline is provided in Naxerova et al.¹⁰. Briefly, all polyguanine genotypes are acquired in triplicate to ensure reproducibility of the stutter distribution. Genotypes are exported from GeneMapper software as tab-delimited text files and filtered to remove replicates whose intensity is below 10% of the average for that patient and marker, eliminated low quality amplifications. Technical replicates are compared to each other to remove outliers and the most representative replicate is selected for further analysis¹⁰.