Current issues and future perspectives of gastric cancer screening

Table 4 Biomarker development process

Phase No.	Aim	Detail
Phase 1	Preclinical Exploratory	Promising directions identified
Phase 2	Clinical Assay and Validation	Clinical assay detects established disease
Phase 3	Retrospective Longitudinal	Biomarker detects disease early before it becomes clinical and a “screen positive” rule is defined
Phase 4	Prospective Screening	Extent and characteristics of disease detected by the test and the false referral rate are identified
Phase 5	Cancer Control	Impact of screening on reducing the burden of disease on the population is quantified

Adapted from reference [32].