Biomarkers in early colorectal, esophageal, and gastric cancer

Gastrointestinal cancer can remain asymptomatic until advanced stages, when treatments tend to be less effective. Therefore, prognosis is poor. Cancer screening programs can help to improve prognosis and patient quality of life through early detection. Biomarkers could prove to be an alternative diagnostic tool and help to select more appropriate treatment. This review focuses on the use of predictive biomarkers in the early diagnosis of colorectal cancer, esophageal cancer, and gastric cancer. Molecular biomarkers based on DNA (methylation of DNA and circulating tumor DNA), RNA, circulating tumor cells, and proteins are being developed for this purpose. These markers have the potential to confirm the diagnosis of the disease in its early stages.