Molecular predictive markers in tumors of the gastrointestinal tract

Table 2 Gene mutations identified in ctDNA of patients with tumors of the gastrointestinal tract and their correlation with possible clinical implications

Gene	Mutation type	Tumor type	Possible clinical implications	Ref.
KRAS/NRAS	Point mutation/amplification	Colorectal/pancreatic cancer	Resistance to anti-EGFR therapy/sensitivity to MEK inhibitors	[88-90]
BRAF	Point mutation	Colorectal cancer	Resistance to anti-EGFR therapy/sensitivity to MEK inhibitors	[88,91]
MET	Amplification/alteration	Colorectal/esophageal cancer	Resistance to anti-EGFR therapy/sensitivity to MEK inhibitors	[92-94]
HER2	Amplification	Colorectal/gastric cancer	Resistance to anti-EGFR therapy/sensitivity to Anti HER2 inhibitors	[95,96]
EGFR	Point mutation	Colorectal/pancreatic cancer	Panitumumab	[97,98]
PIK3CA	Point mutation	Colorectal/pancreatic cancer	mTOR inhibitor	[89]
Ckit	Point mutations	GISTS	Imatinib or dose escalation or alternative TKIs	[99,100]
PDGFRA	Point mutations	GISTS	Imatinib or dose escalation or alternative TKIs	[99,100]

TKI: Tyrosine kinase inhibitors; GIST: Gastrointestinal stromal tumors; EGFR: Epidermal growth factor receptor; mTOR: Mechanistic target of rapamycin.