It has been reported by many authors that the amount and activity of glutathioneS-transferase pi(π)[GST-pi(π)] in many kinds of tumor cells are obviously elevated ascompared with those of corresponding normal cells. In human esophageal tumor tis-sues the expression levels of GST-π mRNA are higher than those in matching normalesophageal mucosa. In the multiple drug-resistant human tumor cells, GST-π gene isactivated through the gene amplification and rearrangement. We have recently It has been reported by many authors that the amount and activity of glutathione S-transferase pi (π) [GST-pi (π)] in many kinds of tumor cells were obvious elevated as asared with those of corresponding normal cells. In human esophageal tumor tis -sues the expression levels of GST-π mRNA are higher than those in matching normalesophageal mucosa. In the multiple drug-resistant human tumor cells, GST-π gene isactivated through the gene amplification and rearrangement.