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Updated: Aug 15, 2026
The Use of Reverse Phase Protein Arrays (RPPA) to Explore Protein Expression Variation within Individual Renal Cell Cancers
Published on: January 22, 2013
RAR-beta(1) overexpression in chromophobe renal cell carcinoma: a novel target for therapeutic intervention?
U Goelden1, S N Ukena, S Pfoertner
1Department of Cell Biology and Immunology, German Research Center for Biotechnology (GBF), D38124 Braunschweig, Germany.
Aim:
Retinoic acid (RA) has proven to possess modest but distinct activity in metastatic renal cell carcinoma (RCC), at least in a subgroup of patients. However, the exact molecular mechanisms leading to success or failure of RA application in individual patients are still unknown. As earlier studies have indicated that in RCC the RA receptor (RAR) beta might play a central role in RA signaling, we investigated the expression of the isoforms RAR-beta(1+2) in primary conventional and chromophobe RCC.
Methods:
We used quantitative RT-PCR methodology to study RAR-beta(1) and RAR-beta(2) expression in ten primary conventional RCC samples (clear cell type), in two chromophobe RCC specimens, and the respective corresponding normal kidney tissues. The housekeeping genes RPS9 and RPLP0 were applied to normalize differences in mRNA quality and quantity.
Results:
In contrast to conventional RCC samples, RAR-beta(1) was significantly overexpressed in both chromophobe tumors compared to the adjacent normal kidney tissue (p=0.03). On the contrary, RAR-beta(2) expression did neither differ significantly between conventional and chromophobe RCC (p=0.91) nor between malignant and normal kidney tissue (p>or=0.47).
Conclusion:
We demonstrate for the first time a significant and specific overexpression of RAR-beta(1) in chromophobe RCC. In future we will have to confirm this result within a larger number of samples.
Insights
Retinoic acid receptor beta 1 (RAR-beta1) is significantly overexpressed in chromophobe renal cell carcinoma (RCC) tumors. This finding may explain differential responses to retinoic acid therapy in specific RCC subtypes.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Retinoic acid (RA) shows activity in metastatic renal cell carcinoma (RCC).
- Molecular mechanisms of RA efficacy in RCC are unclear.
- Retinoic acid receptor (RAR) beta may be key in RA signaling in RCC.
Purpose of the Study:
- Investigate RAR-beta1 and RAR-beta2 expression in primary conventional and chromophobe RCC.
- Determine if RAR-beta isoform expression correlates with RCC subtype.
Main Methods:
- Quantitative RT-PCR used to measure RAR-beta1 and RAR-beta2 mRNA.
- Expression analyzed in 10 conventional RCC, 2 chromophobe RCC, and normal kidney tissues.
- RPS9 and RPLP0 housekeeping genes used for normalization.
Main Results:
- RAR-beta1 significantly overexpressed in chromophobe RCC versus normal kidney tissue (p=0.03).
- No significant difference in RAR-beta1 expression in conventional RCC.
- RAR-beta2 expression did not differ significantly between RCC subtypes or with normal tissue.
Conclusions:
- Significant and specific overexpression of RAR-beta1 identified in chromophobe RCC.
- This finding may elucidate mechanisms of RA response in RCC.
- Further validation in larger cohorts is warranted.
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