The aim of the present study was to determine if p16 methylation in the serum can serve as a candidate marker for the malignancy of colorectal carcinoma, real-time quantitative methylation-specific PCR (RTQ-MSP) was performed for p16 methylation in serum and the relationship between p16 methylation levels and clinicopathological findings of colorectal carcinoma was evaluated.
Results: The p16 methylation score significantly increased with tumor stage (stage I=0.94+/-0.47, stage 11=2.33+/-0.90, stage 111=8.49+/-2.37, stage IV=10.03+/-4.30) (p=0.021; ANOVA). The p16 methylation score was significantly higher in patients with lymph node metastasis (p=0.001) and tumor invasion to the veins (p=0.020). The cumulative survival of patient groups according to the p16 methylation score (more or less than 1) was examined. Interestingly, the group with a high p16 methylation score showed significantly worse survival rates than the group with a low p16 expression score (p= 0.006).
Conclusion: The p16 methylation score might serve as a new parameter for the prognosis of colorectal carcinoma. Moreover, p16 methylation was found in the serum of patients in all clinical stages, suggesting that early colorectal carcinoma could be detected using the RTQ-MSP method.