Methylation status of multiple genes in colorectal cancer tissues and its clinical significance

AIM: The aim of the present study was to detect the methylation status of multiple genes (Syk, CDH1 and TIMP-3) in colorectal cancer (CRC) tissues, to investigate the roles in the pathogenesis of CRC, to investigate whether methylation of multiple genes was associated with recurrence and metastasis of CRC, and to evaluate its ability to predict the prognosis of CRC. METHODS: Nested methylation-specific PCR (n-MSP) were used to detect methylation status of spleen tyrosine kinase (Syk) from 120 CRC tissues and the methylation status of CDH1 and tissue inhibitor of metalloproteinase-3 (TIMP-3) from 100 CRC tissues. RESULTS: We found that methylation in one or more genes, co-methylation in two genes and three genes were detected in 74%, 21%, and 8% of CRC tissues. No significant correlation between three genes co-methylation and lymph node metastasis (2=0.725，P>0.05) was observed. The methylation of CDH1 gene, but not Syk or TIMP-3 gene, was significantly related with liver and lung metastasis of CRC (2=6.938，P<0.01). The methylation of Syk or TIMP-3, and co-methylation of CDH1 and TIMP-3 were risk factors in the prognosis of colorectal cancer after surgical treatment, and three genes co-methylation was not a risk factor. CONCLUSION: Our results indicate that methylation of multiple genes exists in CRC tissues. The methylation of multiple genes is not a necessary factor in the pathogenesis, metastasis and recurrence of CRC, and also it is not a necessary prognostic factor in CRC.