Expressions of Multidrug Resistance-Related Genes in Gastric Cancer Tissue and Normal Gastric Mucosal Tissue / Journal of the Korean Cancer Association, 대한암학회지

ABSTRACT

PURPOSE: This study was conducted to evaluate the expressions of the mdr1 gene and the MRP gene in tumor and adjacent normal gastric tissues. MATERIALS AND METHODS: The specimens were obtained from 53 patients who had gastric cancer. None of these patients had received any kind of preoperative chemotherapy. The reverse transcription polymerase chain reaction and immunohistochemical stain were used to check the level of expressions of mRNAs and their associated proteins. RESULTS: Highly positive expressions of mdr1 mRNA, MRP mRNA, p-glycoprotein, and MRP (multidrug resistance associated protein) were observed in the tumor and the adjacent normal tissues. Most tumor tissues coexpressed mdr1 mRNA and MRP mRNA significantly (p<0.001). The expression of these genes in the tumor was much stronger than in the normal counterpart tissues. The expression of the p-glycoprotein was correlated only with the pathological stage (p<0.05). MRP expression was correlated with lymph node metastasis (p<0.05). CONCLUSION: Normal gastric tissue showed strong physiologic expressions of the mdr1 and MRP genes. Overexpressions of these genes were observed in gastric cancer tissue. The presence of multidrug resistance should be considered when planning anticancer chemotherapy for treating gastric cancer.