Ojbective To search for circulating DNA as a biomarker for the cancer burden of patients^[1].Methods Methylation specific PCR(MSP),according to Herman et al,was used to identify this epigenetic modification of DNA fro...Ojbective To search for circulating DNA as a biomarker for the cancer burden of patients^[1].Methods Methylation specific PCR(MSP),according to Herman et al,was used to identify this epigenetic modification of DNA from serum and tissue of 111 patients with different cancers.In parallel the mutant K-ras gene was analyzed in 55 cases for comparison.Results Methylation of the p16 gene was found in serum or cancer tissue in about 50% of patients with a statistically significant difference Results Methylation of the p16 gene was found in serum or cancer tissue in about 50% of patients with a statistically significant difference to healthy controls(P<0.05).There was no difference between the DNA from the tumor and from the neighboring normal tissue or from sereum in early cancer.The positivity rate increased with progression of the tumor.20 days after the operation methylated DNA nearly disappeared.The positivity rate for mutant K-ras was only 30% and thus much lower than that of methlated DNA.The combination of the two markers increased the positivity rate of tumors by 13%.Conclusion The detection of methylation of the p16 gene by MSP combined with mutant K-ras is serum of cancer patients would be a very effective method to estimate the cancer burden.展开更多
文摘Ojbective To search for circulating DNA as a biomarker for the cancer burden of patients^[1].Methods Methylation specific PCR(MSP),according to Herman et al,was used to identify this epigenetic modification of DNA from serum and tissue of 111 patients with different cancers.In parallel the mutant K-ras gene was analyzed in 55 cases for comparison.Results Methylation of the p16 gene was found in serum or cancer tissue in about 50% of patients with a statistically significant difference Results Methylation of the p16 gene was found in serum or cancer tissue in about 50% of patients with a statistically significant difference to healthy controls(P<0.05).There was no difference between the DNA from the tumor and from the neighboring normal tissue or from sereum in early cancer.The positivity rate increased with progression of the tumor.20 days after the operation methylated DNA nearly disappeared.The positivity rate for mutant K-ras was only 30% and thus much lower than that of methlated DNA.The combination of the two markers increased the positivity rate of tumors by 13%.Conclusion The detection of methylation of the p16 gene by MSP combined with mutant K-ras is serum of cancer patients would be a very effective method to estimate the cancer burden.
