Copyright ©The Author(s) 2018.
World J Gastrointest Oncol. Jul 15, 2018; 10(7): 145-158
Published online Jul 15, 2018. doi: 10.4251/wjgo.v10.i7.145
Table 1 Biomarker types and definitions
Biomarker typeObjective
Diagnostic biomarkerThese aim to identify the type of cancer, e.g., PSA, CEA. They may also be used to monitor or detect disease recurrence
Pharmacological biomarkerThese are used to measure response to a specific drug treatment. They are based on accurate pharmokinetic data and measure treatment response in early drug trials, e.g., drug therapy to angiogenesis
Predictive biomarkerThese are used to identify individuals who will most likely show a survival benefit to a specific targeted treatment, e.g., improvement in local recurrence risk following treatment for circumferential resection margin involvement
Prognostic biomarkerThese indicate the progress of disease and to estimate the risk of disease recurrence for example. They are used to estimate survival outcome and are independent of treatment strategy, e.g., nodal disease
Risk/predisposition biomarkerThese aim to identify individuals who are at significant risk of developing tumours, e.g., MLH1 gene
Screening biomarkerThese are used to identify disease at an early stage, e.g., PSA
Surrogate response biomarkerThese can be used as an alternative to a clinically meaningful endpoint. Therefore there must be correlation with a clinical endpoint, e.g., CEA
Table 2 Candidate liquid biopsy/circulating miRNA biomarkers[145]
Expression levelDiagnostic biomarkerPrognostic biomarker (malignant potential, tumor recurrence)Predictive biomarker (chemosensitivity)
HighmiR-92a, miR-141, let-7a, miR-1229, miR-1246, miR-150, miR-21, miR-223, miR-23a, miR-378miR-141, miR-320, miR-596, miR-203miR-106a, miR-484, miR-130b
LowmiR-15a, miR-103, miR-148a, miR451