Aberrant expression of Pax-2 mRNA in renal cell carcinoma tissue and parenchyma of the affected kidney.

BACKGROUND: Pax proteins are transcription factors that demonstrate oncogenic properties and appear to play a crucial role in ontogenesis. Pax-2 is expressed in early kidney organogenesis, Wilms' tumor and renal cell carcinoma. In order to determine whether the expression of Pax-2 mRNA is a frequent and specific event in renal cell carcinoma, its expression in nephrectomized specimens and cell lines was investigated. METHODS: The expression of Pax-2 mRNA was examined by reverse transcription polymerase chain reaction in 55 nephrectomized specimens, nine renal parenchyma specimens from patients without renal cell carcinoma and 16 cell lines from various malignant diseases. RESULTS: All tumor tissue specimens expressed Pax-2 mRNA. In addition, 38 of 55 specimens from the renal parenchyma of the affected kidney expressed Pax-2 mRNA. In contrast, only two of the nine kidney specimens from patients without renal cell carcinoma expressed Pax-2 mRNA, indicating that expression of this protein is significantly higher in renal cell carcinoma (P < 0.01). All three cell lines from renal cell carcinoma expressed Pax-2. In contrast, Pax-2 was only expressed in two of three cell lines from transitional cell carcinoma and in none of the other lines. CONCLUSION: The results indicate that Pax-2 expression is a frequent and highly specific event in renal cell carcinoma.