Published online Aug 14, 2022. doi: 10.3748/wjg.v28.i30.4120
Peer-review started: November 26, 2021
First decision: January 8, 2022
Revised: January 21, 2022
Accepted: July 18, 2022
Article in press: July 18, 2022
Published online: August 14, 2022
Gastric cancer (GC) is a common malignant tumor in the digestive tract. Although the 5-year survival rate of GC is enhanced with the combination of chemotherapy and surgery, its mortality remains high due to the diagnosis at an advanced stage. It is essential to develop a new method to diagnose GC at an early stage.
Fusobacterium nucleatum (Fn) primarily colonized in the oral cavity, has been detected in tissues of GC in recent years. We wondered whether there is a correlation between salivary Fn and GC.
The research purpose was to find a new simple and effective biomarker to diagnose GC.
The abundance of Fn in saliva was quantified by droplet digital polymerase chain reaction in 120 GC patients, 31 atrophic gastritis (AG) patients, 35 non-AG (NAG) patients, 26 gastric polyp patients, and 20 normal controls (NC). The diagnostic value of Fn was evaluated and compared with traditional serum tumor markers, including carcinoembryonic antigen (CEA), carbohydrate antigen (CA)19-9, CA72-4, ferritin, and sialic acid. Transwell and wound-healing assays were conducted to assess the influence of Fn infection on GC cells. Western blot analysis was performed to detect the expression of epithelial-mesenchymal transition (EMT) markers.
Fn had favorable diagnostic value in classifying GC from NC and benign diseases, which was superior to those traditional serum tumor markers, such as CEA, CA19-9, CA72-4, ferritin, and sialic acid. Salivary Fn level was positively associated with the GC TNM stage and lymph node metastasis. Further, in vitro experiments revealed that Fn could promote the migration and invasion of GC cells. Western blot analysis indicated that Fn infection decreased the expression of epithelial marker such as E-cadherin, and increased the expression of mesenchymal markers such as N-cadherin, vimentin, and snail.
Fn in saliva could be used as a promising biomarker to diagnose GC, and Fn infection could promote GC metastasis by accelerating the EMT process.
Human saliva is a unique bio-fluid resource with huge clinical diagnostic and risk assessment capacity. Salivary Fn has promising value for diagnosing GC.