Expression patterns of multidrug-resistance (MDR1), multidrug resistance-associated protein (MRP),glutathione-S-transferase-pi (GST-pi) and DNA topoisomerase II (Topo II) genes in renal cell carcinomas and normal kidney.
OBJECTIVE
Expression levels of the multidrug-resistance (mdr1), multidrug resistance-associated protein (MRP), glutathione-S-transferase-pi (GST-pi) and DNA topoisomerase II (Topo II) genes in normal kidney and renal cell carcinomas were analyzed to study the complexity of the roles of these genes.


METHODS
The reverse transcription-polymerase chain reaction (RT-PCR) assay was used with beta 2 microglobulin (beta 2 m) as the internal control.


RESULTS
In normal kidneys, the expression levels of the 4 genes in individual normal kidney samples correlated significantly with one another. Comparisons of the expression levels between normal kidneys and renal cell carcinomas showed that only the mean MRP gene expression level was higher in renal cell carcinomas than in normal kidneys (p = 0.018). The expression patterns of the 4 genes in renal cell carcinomas differed markedly for nonpapillary and papillary tumors. The mean MRP/beta 2 m ratio for the papillary type was significantly lower than that for the nonpapillary alveolar type carcinoma (p = 0.004). The 4 genes showed moderate positive correlations with one another in alveolar type renal carcinoma similar to the correlations observed in normal kidneys. In contrast, in papillary type, MRP expression was inversely correlated with mdr1 and Topo II expression.


CONCLUSIONS
Differences in cytogenetic changes, origins and natural histories between papillary and nonpapillary carcinoma may be associated with these distinct expression patterns of the resistance-related genes. Further study is required to clarify whether the differences in the expression patterns between these 2 structural types of carcinoma affect their chemosensitivities and clinical outcomes.
Kim
W J
WJ
Department of Urology and Pathology, Faculty of Medicine, Kyoto University, Japan.
Kakehi
Y
Y
Kinoshita
H
H
Arao
S
S
Fukumoto
M
M
Yoshida
O
O
D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D002292:Carcinoma, Renal Cell / Q000235:genetics*; D004250:DNA Topoisomerases, Type II / Q000096:biosynthesis / Q000235:genetics*; D018432:Drug Resistance, Multiple / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D005982:Glutathione Transferase / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D007668:Kidney / Q000378:metabolism; D007680:Kidney Neoplasms / Q000235:genetics*; D016014:Linear Models; D008969:Molecular Sequence Data; D027425:ATP-Binding Cassette, Sub-Family C Proteins
D018528:ATP-Binding Cassette Transporters; D004250:DNA Topoisomerases, Type II; D005982:Glutathione Transferase; D027425:ATP-Binding Cassette, Sub-Family C Proteins