Aim: To study the relationship between expression of oncogenes and multiple drug resistant (MDR) phenotype.
Methods: The drug resistant level of HL60 cell line and its sublines were determined with flow cytometry. RNA Dot blot hybridization was used to identify the expression of oncogenes and mdr-1 gene.
Results: The expression of mdr-1 gene was in the opposite relation with c-myc expression, but in the positive relation with c-H-ras gene expression in the multiple drug resistant cell lines. In non-MDR cell line HL60/RA, the expression levels of mdr-1, c-myc, and c-H-ras were the same as HL60 parental cells.
Conclusion: Multiple drug resistance is related to not only mdr-1 expression, but also some oncogenes expression level.