High frequency of promoter hypermethylation of the death-associated protein-kinase gene in nasopharyngeal carcinoma and its detection in the peripheral blood of patients

Clin Cancer Res. 2002 Feb;8(2):433-7.

Abstract

Purpose: Death-associated protein (DAP)-kinase gene is frequently inactivated by promoter hypermethylation in cancer. The aim of this study was to evaluate the promoter methylation status of the DAP-kinase gene in nasopharyngeal carcinoma (NPC).

Experimental design: The methylation status was evaluated by methylation-specific PCR (MSP). Thirty-two NPC biopsy specimens, plasma and buffy coat of 12 patients, 5 NPC cell lines, 3 normal nasopharyngeal biopsy tissues, and 2 normal nasopharyngeal epithelial primary cultures were included in this study.

Results: There was no promoter hypermethylation in all 3 normal nasopharyngeal tissues and 2 normal nasopharyngeal primary cultures. Hypermethylation was found in 24 (75%) NPC primary tumor biopsies and 4 (80%) NPC cell lines. Of the 24 patients with hypermethylation of DAP-kinase promoter in the primary tumors, 12 patients had their plasma and buffy coat DNA available for MSP study. Hypermethylated DAP-kinase promoter was detectable in 5 patients in the plasma but not in the buffy coat, 2 patients in the buffy coat but not in the plasma, and 1 patient in both plasma and buffy coat. Four patients had no detectable hypermethylated DAP-kinase promoter in both plasma and buffy coat. Hypermethylation of DAP-kinase promoter was found in both early- and late-stage NPC.

Conclusions: Our results show that hypermethylation of the DAP-kinase promoter is a common early event in NPC. The high frequency of identification of hypermethylated DAP-kinase promoter in plasma and buffy coat of NPC patients illustrates its potential clinical application as tumor marker for the diagnosis and monitoring of treatment result.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis Regulatory Proteins
  • Biopsy
  • Calcium-Calmodulin-Dependent Protein Kinases / biosynthesis
  • Calcium-Calmodulin-Dependent Protein Kinases / blood*
  • Calcium-Calmodulin-Dependent Protein Kinases / genetics*
  • Carcinoma / blood
  • Carcinoma / enzymology*
  • DNA Methylation*
  • Death-Associated Protein Kinases
  • Female
  • Humans
  • Male
  • Nasopharyngeal Neoplasms / blood
  • Nasopharyngeal Neoplasms / enzymology*
  • Promoter Regions, Genetic*
  • Sulfites / metabolism

Substances

  • Apoptosis Regulatory Proteins
  • Sulfites
  • Death-Associated Protein Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases