Investigators have a plan to conduct nested case-control study to investigate the association between serum cholesterol levels including TC, HDL-C, LDL-C, triglyceride (TG), apolipoproteins and gastric neoplasm. In addition, further analyses were performed to evaluate the possible role of the serum cholesterol as a predictor for the differentiation and prognosis of gastric neoplasm.

Although its incidence has declined, gastric cancer remains one of the most common causes of cancer morbidity and mortality worldwide.Since the stage of gastric cancer at the time of detection correlates with prognosis, secondary prevention is important. Screening of asymptomatic individuals for gastric cancer has been shown to increase the detection of early gastric cancer (EGC), which has a 5-year overall survival (OS) rate exceeding 90%.

Gastric carcinogenesis is a multi-factorial process that includes environmental, socioeconomic, and lifestyle factors. Many of risk factors, including dietary factors, chronic atrophic gastritis, intestinal metaplasia, and H. pylori infection, alcohol consumption, and aspirin have been investigated. Although the specific correlation between serum cholesterol and gastric cancer is not fully understood, inverse relationships have been observed between serum total cholesterol (TC) levels and cancer, and recent analyses of randomized controlled trials showed significant inverse associations between high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) and the risk of incident cancers. Lower lipoprotein cholesterol in cancer patients may be due to the enhanced activity of the lipoprotein cholesterol receptor pathway and to the increased demand for cholesterol during tumor development and lymphatic spread. Some suggested that the preexisting tumor might have resulted in low serum cholesterol, which is called "preclinical cancer effect" or "unsuspected sickness". In another study, LDL-C has been reported to affect host immune system cells.

In our previous study, investigators found that serum HDL-C and LDL-C levels were associated with the risk, resectability, and prognosis of gastric cancer. There are several cohort studies reported that low serum cholesterol levels are associated with incident cancer, including gastric cancer. However, most studies regarding the serum cholesterol and gastric cancer investigated gastrectomized patients, and showed the association between low serum cholesterol levels and lymph node metastasis or submucosal invasion. Furthermore, there are only few studies evaluated the association between LDL-C of apolipoproteins and gastric cancer. Therefore investigators conducted nested case-control study to investigate the association between serum cholesterol levels including TC, HDL-C, LDL-C, triglyceride (TG), apolipoproteins and gastric neoplasm. In addition, further analyses were performed to evaluate the possible role of the serum cholesterol as a predictor for the differentiation and prognosis of gastric neoplasm.

Inclusion Criteria:

• All subjects who visited the department of gastroenterology, surgery, or Healthcare Screening & Promotion Center at Asan Medical Center and diagnosed as gastric cancer

Exclusion Criteria:

• Subjects who has history about drug for cholesterol, diabetes, liver disease, and/or thyroid disease.
• Subjects who do not want to be enrolled this study

All subjects who visited the department of gastroenterology, surgery, or Healthcare Screening & Promotion Center at Asan Medical Center and diagnosed as gastric cancer