Clonal architecture of BMPC and ctDNA mutations before and after IRd. (A) Changes in mutant allele frequencies in BMPC and ctDNA before and after IRd in 4 representative cases. The same mutations of KRAS, TP53, DIS3, BRAF, NRAS, and ATM are shown in the same color in BMPC and ctDNA within the same case. Open circles represent undetectable levels by each sequencing method; ND, not detected. (B) Number of emerging and disappearing mutations in ctDNA before and after IRd therapy in 94 cases. Emerging mutations are defined as those (1) which were present only after IRd, or (2) whose allele frequency after IRd was ≥4-times higher than before IRd. Disappearing mutations were defined as those (1) which were present only before IRd, or (2) whose allele frequency after IRd was ≥4-times lower than before IRd. Genes with emerging and/or disappearing mutations detected in ≥2 cases are shown. (C-D) Frequency of cases with (C) KRAS and (D) TP53 mutations according to the number of prior regimens, detected by BMPC-seq (n = 163) and ctDNA-seq (n = 259). The number of cases is shown in parenthesis. Odds ratio (OR) and P value are calculated using 2-sided Fisher exact test.