KRAS and colorectal carcinoma: Some authors investigated the concordance between cfDNA and corresponding tissues for KRAS mutational status in CRC patients, finding highly variable results ranging from 14% concordance to 100%.6 In our cohort of patients, we found an optimal concordance (89.5% for the presence of any mutation in KRAS, 84% for the specific KRAS mutation), independently from time interval between tissue and cfDNA sequencing, which in some cases reached 3 years.