The 100% of NPC cell lines, 80% of primary NPC and 22.2% of CN tissues showed methylation in DLC-1 promoter, while DLC-1 expression was recovered in seven NPC cell lines after 5-aza-dC treatment.
These results demonstrate that DLC-1 gene can partially reverse the malignant phenotype of NPC cells by changing the tumor-related gene expression profile, and may be a candidate tumor suppressor gene and a promising diagnostic and therapeutic target in NPC.
Taken together, our results suggest that DLC-1 might be an NPC-related tumor suppressor gene affected by aberrant promoter methylation and gene deletion.