Elevated level of spindle checkprotein MAD2 correlates with cellular mitotic arrest, but not with aneuploidy and clinicopathological characteristics in gastric cancer

AIM: To study the relevance of spindle assembly checkprotein MAD2 to cellular mitotic status, aneuploidy and other clinicopathological characteristics in gastric cancer.METHODS: Western blot analyses were performed to analyze the protein levels of MAD2 and cyclin B1 in the tumorous and adjacent nontumorous tissues of 34 gastric cancer patients. Cell cycle distribution and DNA ploidy of cancer tissues were also determined by flow cytometry.Conventional statistical methods were adopted to determine the relevance of abnormal MAD2 level to mitotic status,aneuploidy and clinicopathological parameters.RESULTS: Out of 34 gastric cancer patients 25 (74%)exhibited elevated MAD2 levels in their tumorous tissues compared with the corresponding nontumorous tissues.Elevation of MAD2 levels significantly correlated with the increased levels of cydin B1 expression and G2/M-phase distribution (P = 0.038 and P = 0.033, respectively), but was not relevant to aneuploidy. The gastric cancer patients with elevated MAD2 levels showed a tendency toward better disease-free and overall survival (P＞0.05). However, no association was found between elevated MAD2 levels and patients' clinicopathological characteristics.CONCLUSION: Elevation of MAD2 level is present in 74%of gastric cancer patients, and correlates with increased mitotic checkpoint activity. However, elevation of MAD2level is not associated with patients' aneuploidy and any of the clinicopathological characteristics.