KRAS and digestive system neoplasm: However, mutations can be detected both in patients with intraductal papillary mucosal neoplasms (IPMNs) and in healthy subjects, suggesting that exoDNA biopsy is more suitable for the assessment of cancer risk than for definitive cancer diagnosis.97 Similar to exoDNA, circulating cell-free tumor DNA (cfDNA) can be used to detect KRAS mutations in many gastrointestinal tumors.98 Allenson et al. compared the diagnostic value of exoDNA and cfDNA for identifying PDAC patients via KRAS mutations.