Molecular Detection of p16 Promoter Methylation in the Serum of Patients with Esophageal Squamous Cell Carcinoma

Purpose and Experimental Design: Recent evidence shows that the presence of promoter hypermethylation of tumor suppressor genes has been demonstrated in the serum DNA of patients with various cancers such as lung, liver, and head and neck cancer. We have examined promoter hypermethylation of the p16 gene in esophageal squamous cell carcinoma (SCC) using methylation-specific PCR to detect tumor DNA in the serum. Results: Aberrant promoter methylation of the p16 gene was detected in 31 of 38 (82%) esophageal SCCs. Subsequently, we tested for promoter methylation in the paired serum DNA of 31 patients with a p16 alteration in the primary tumor. We found that 7 of these 31 (23%) patients had the same methylation changes in the serum DNA. Conclusions: This result indicates that promoter methylation present in the tumors of esophageal SCC patients can be detected in the serum of the same patient and that this approach can potentially be used for the screening and monitoring of the disease.