Liquid biopsy to detect resistance mutations against anti-epidermal growth factor receptor therapy in metastatic colorectal cancer

Table 1 Frequency of acquired KRAS resistance mutations in patients with stage IV colorectal cancer treated with cetuximab or panitumumab

Ref.	n wt KRAS patients at baseline	Analysis technique	Mutations or amplifications in KRAS/NRAS	Most frequent mutations
Vitiello et al[18], 2019	30	ctDNA/RT-qPCR	10 (30%)	KRAS Q61x (4)
				KRAS G12x (3)
Diaz et al[33], 2012	24	ctDNA/BEAMing	9 (36%)	KRAS G12x (9)
Pietrantonio et al[41], 2017	11	ctDNA/ddPCR	4 (36%)	KRAS Q61H (2)
Vidal et al[42], 2017	18	ctDNA/BEAMing	7 (39%)	KRAS G12x (5)
				NRAS Q61x (3)
Morelli et al[44], 2015	62	ctDNA/BEAMing	27 (43%)	KRAS G12x (10)
				KRAS Q61x (9)
Strickler et al[45], 2018	42	ctDNA/NGS DNAseq	26 (62%)	KRAS Q61H (22)
				KRAS G12A (5)
Yamada et al[46], 2020	19	ctDNA/ddPCR	16 (84%)	KRAS Q61H (10)
				KRAS G12V (9)
Kim et al[48], 2018	164	ctDNA/NGS DNA seq	53 (32.3%)	KRAS exon 3 (A59x o Q61x) (20)
Takayama et al[75], 2018	25	ctDNA/ddPCR	9 (36%)	KRAS Q12S (5)
				KRAS Q12D (4)

ctDNA: Circulating tumor DNA; ddPCR: Droplet digital PCR; NGS: Next-generation sequencing; BEAMing: Beads, Emulsion, Amplification, Magnetics.