Relationship between genetic instability of nm23H1 gene and clinical pathological behaviors in gastric cancer and colonic cancer

AIM: To study the relationship between genetic instability of nm23H1 gene and clinical pathological behaviors in Chinese with gastric cancer and colonic cancer, and provide experimental basis for the mechanism of nm23H1 gene and tumor metastasis. METHODS: This study was conducted on 40 gastric carcinomas and 30 colonic carcinomas. Techniques such as DNA extraction from formalin-fixed paraffin-embedded tissues, PCR-SSCP, ordinary silver stain were used to study microsatellite instability (MSI) and loss of heterozygosity (LOH) of locus D17S396. Envision immunohistochemistry and Leica-Qwin computer imaging techniques were used to assess the expression of nm23H1 protein. RESULTS: In both gastric cancer and colonic cancer, the frequency of MSI was higher in TNM stageⅠandⅡthan that in stage Ⅲ and Ⅳ, while LOH was just opposite. Moreover, the frequency of LOH in lymph node metastasis cases was significantly higher than that without lymph node metastasis cases. The positive frequency of nm23H1 protein with lymph node metastasis was lower than that without lymph node metastasis cases. TNM stage III and IV also exhibited lower nm23H1 protein positive frequency compared with stage I and II. CONCLUSION: MSI and LOH can control the carcinogenesis and metastasis of gastric cancer and colonic cancer through different approaches. MSI may be an early period molecule marker of gastric cancer and colonic cancer. In contrast, LOH appears mostly in the late period of gastric cancer and colon cancer, indicating a high aggressive and poor prognosis.