- Helicobacter pylori infection: Helicobacter pylori (H pylori) is a bacterium that generally infects the stomach and the duodenum and causes inflammation in these organs. An increased incidence of stomach cancers has been observed in individuals with the H pylori.
- Chronic atrophic gastritis: It is a condition in which long-term inflammation of the stomach mucosa causes the loss of stomach mucosal cells and subsequent replacement with the intestinal and fibrous tissue. Various studies have shown that the patients with atrophic gastritis are at increased risk of developing stomach cancer.
- Diet: Smoked or salted foods, low intake of fruits and vegetables, improperly prepared/stored food, foods rich in nitrates, and foods contaminated with aﬂatoxin are considered to elevate the risk of gastric cancer.
- Industrial/Occupational exposure: Regular exposure to heavy metals or harmful gases/fumes, especially those encountered in coal, metal, or rubber industry, has been found to increase the risk of stomach cancer.
- Genetic Cancer Predisposition Syndromes: Some inherited cancer predisposition syndromes have been reported to be associated with a high incidence rate of stomach cancer.
Following are some examples: Hereditary diffuse stomach cancer (caused by mutation in the CDH1 gene); Lynch syndrome or hereditary non-polyposis colorectal cancer (HNPCC, generally caused by mutation in the MLH1 or MSH2 gene); Familial adenomatous polyposis (FAP, caused by mutations in the APC gene); Li-Fraumeni syndrome (caused by mutation in the TP53 gene), and mutations in the breast cancer genes – BRCA1 or BRCA2.
- Older age individuals especially men are at significantly higher risk of developing gastric cancer.
Smoking, heavy alcohol intake, obesity, low socioeconomic status, infection with Epstein-Barr virus (EBV), and some disorders like Menetrier disease, are other reported gastric cancer risk factors.