The higher TMB observed in this study may be explained by the fact that patients enrolled underwent multiple lines of systemic therapy, leading to clonal evolution and changes in the variational landscapes that may not present in the primary tumor DNA.21 The rate of KRAS and NRAS variation was 64% and 2% based on tissue analysis, and 78% and 10% based on cfDNA analysis (eTable 1 in Supplement 2). Here, NRAS is linked to neoplasm.