The Clinical Research On The Expression Of COX-2 In The Serum Of Gastroenteric Malignant Tumor Patients

Gastric cancer is one of the most common malignant tumors which causes approximately 600,000 deaths a year all over the world. In China, gastric cancer is the most common cause of death due to cancer .Colon cancer rangs third in number in diagnosed cancer and is the second most common cause of cancer death in the US, with approximately 145,000 new cases and 56,000 deaths a year. The incidence of colorectal cancer is high in developed countries, with approximately half of the Western population developing adenoma by the age of 70. Most colorectal malignancies are sporadic, but heredity plays a role in some cases. Familial adenomatous polyposis (FAP) is one of the best characterized inherited colon cancers, with patients developing hundreds to thousands of preneoplastic colonic polyps in early adulthood. Colon cancer is inevitable in FAP patients who deny prophylactic surgical options. In addition to colonic lesions, FAP patients are also apt to develop other malignancies, including ampullary carcinomas and hepatoblastomas.It is reported that a long-term aspirin intake decreased the relative risk of developing colon cancer with a rate of 40% and reduced deaths of esophageal, gastric and rectal cancers. Furthermore, in 1998, Waddell et al. discovered that long-term treatment with sulindac for some other diseases decreased the number of colonic polypi in patients with familial adenomatous polyposis. Both Aspirin and sulindac are Nonsteroidal antiinflammatory drugs (NSAIDs), and NSAIDs is cyclooxygenase(COX) inhibitor, therefore people start to pay attention to the relation between COX and alimentary tract tumor. In addition, studies documented that COX-2 is overexpressed in 40% of human colon adenomas and in 80% of colon adenocarcinomas compared with normal mucosa, but theexpression of COX-l in different mucosa tissue is not diverse. for this reason,COX-2 maybe play an important role in tumorigenesis and progression of gastroenteric malignant tumor.Cyclooxygenases (COX) is the key rate-limiting enzymes in the synthesis of prostaglandins. There are at least two isoforms of COX in mammal: COX-1 and COX-2. recently, the reports about COX-3 also appeared. COX-1 is constitutively expressed in various types of cells and plays important roles in homeostasis. It is involved in maintenance of the gastric mucosa, in regulation of renal blood flow in the afferent vessels of the kidney and of platelet aggregation. Whereas COX-2 is usually absent but is inducible by various cytokines, growth factors and mitogens. At present, the exact function of COX-2 is indefinite. In the last 20 years, numerous researches demonstrated that COX-2 was involved in inflammation and tumorigenesis,cancer progression .Following are the possible carcinogenesis mechanisms of COX-2:1. promote proliferation and differentiation of tumor cell; 2. inhibit the apoptosis of tumor cell; 3. promote tumor angiogenesis; 4. promote tumor cell invasive growth and metastasis; 5. inhibit cell immune surveillance function and tumor-kill function; 6. activate proto-oncogene and induce anti-oncogene deletion or mutation.In this study, we selected primarily 98 gastric cancer or colorectal cancer patients and 30 healthy persons as subjects. All the patients had been treated in hospital from January 2005 to December 2006 and were confirmed using pathology methods.While healthy persons were selected from medical examination people. We adopt enzyme linked immuno sorbent assay (ELISA) to detect the concentration of COX-2 protein in the serum of all the subjects.The result showed that the concentration of COX-2 protein in the serum is higher in gastric cancer and colorectal cancer patients compared with healthy person.A value of P<0.05 was considered statistically significant. COX-2 protein levels in the serum is obviously higher in the advanced stage patients than patients in the earlier period. A value of P<0.05 was considered statistically significant.In conclusion, our study demonstrated that COX-2 was overexpressed in the serum of gastric cancer and colorectal cancer patients. The COX-2 expression level correlated with tumer stage. These results suggest that COX-2 maybe play an important role in tumorigenesis and cancer progression of gastroenteric malignant tumor.