Purpose: The aim of this study was to investigate whether the expression of the ligand-gated Ca2⁺channel transient receptor potential vanilloid type-1 (TRPV1) in primary human renal cell carcinoma (RCC) is associated with clinicopathological features.
Patients and methods: Fresh and frozen primary tumor and normal peritumoral kidney tissues from 127 patients diagnosed with RCC were analyzed for TRPV1 expression by quantitative reverse transcription polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry.
Results: Quantitative RT-PCR revealed that TRPV1 was decreased 3.20-fold in RCC tissue vs normal peritumoral kidney tissue (p =0.012). Significantly different TRPV1 mRNA expression was detected in RCC tissues of different Fuhrman grades and histopathological subtypes (F=4.282, p =0.015 and F=5.205, p =0.014, respectively). Decreased TRPV1 expression was correlated with RCC histopathological subtype (R=-0.554, p =0.003) and Fuhrman grade (R=−0.525, p =0.006). Western blot analysis of TRPV1 protein expression showed similar results. Immunohistochemical analysis showed strong expression of TRPV1 in kidney tubules but demonstrated weak or no immunostaining in RCC tissues.
Conclusion: TRPV1 expression was decreased in RCC, which was significantly associated with tumor Fuhrman grades and histopathological subtypes. It seems to suggest that TRPV1 expression may be a valuable tool to predict the extent of RCC progression.
Keywords: renal cell carcinoma, TRPV1, Fuhrman grade, histopathological subtype, prognostic factor