Overview of MDM2 and B-RAF Expression in Gastric Lesions

BACKGROUND: Globally, gastric cancer (GC) it is the fourth most common cancer and the third cause of cancer-related deaths. Overexpression of MDM2 and B-RAF appeared to be increased in malignancy and associated with poor prognosis in several human tumours, but their role in gastric cancer remains controversial. AIM: We had investigated the immunohistochemical expression of MDM2 and B-RAF in 136 gastric lesions with/without H. pylori association. MATERIAL AND METHODS: Studied specimens include chronic gastritis (32), intestinal type GC (70), diffuse GC (22) and gastrointestinal stromal tumours (GIST) (12). RESULTS: MDM2 expression increased significantly in intestinal GC compared to other groups (p < 0.001), while B-RAF expression increased significantly in GIST compared to other groups (p < 0.001). H. pylori increased expression of MDM2 in intestinal GC cases but did not affect B-RAF expression. MDM2 expression correlated with high grade of tumor differentiation (p < 0.001), deep invasion (p < 0.05), nodal metastases (p < 0.05) and distant metastases (p < 0.1) in intestinal GC, while B-RAF expression did not correlate with TNM stage (p < 0.1). CONCLUSION: MDM2 up-regulation was more frequent in intestinal GC, while B-RAF up-regulation was more frequent in GIST compared to other groups; MDM2 expression in intestinal GC was correlated with H. pylori association, high grade of differentiation, deep invasion, nodal and distant metastases, meanwhile, B-RAF expression was correlated with high-grade intestinal GC but did not correlate with H. pylori or TNM stage. The possible role of both MDM2 and B-RAF in predicting progression of gastric tumours and prognosis deserves further investigations.