The cure rate of gastric cancer

a highly aggressive digestive tract malignancy

can reach more than 90%

if it can be treated by surgery at the early stage. However

due to the lack of obvious symptoms and sensitive tumor markers in the early stage of gastric cancer

nearly 80% of gastric cancer patients in China are in advanced stage when first diagnosed. As an emerging molecular detection technology

liquid biopsy is noninvasive

quick

economic and reproducible

and has better sensitivity and specificity than serological tumor markers. It can also detect tumor in advance of pathological biopsy

which brings a bright light for early detection and risk assessment of gastric cancer. Yet

liquid biopsy has not been widely used in clinic due to many factors. One of the main reasons is that most samples of traditional liquid biopsies are from patient’s blood (including plasma and serum)

and the low concentration of cancer-derived components in the blood samples limits the ability of liquid biopsy to detect and warn occurrence or recurrence of early cancer. Recent research has further expanded the concept of liquid biopsies

finding that biopsies derived from fluids other than blood

called non-blood derived liquid biopsy

can better screen

diagnose and monitor tumors

promising to advance the use of liquid biopsies for the early diagnosis of gastric cancer. Therefore

by searching the relevant literature in recent years

we analyzed the advantages and challenges of non-blood derived liquid biopsy compared with traditional liquid biopsy

and reviewed the research advances of liquid biopsy derived from saliva

gastric juice

gastric wash and urine in gastric cancer.