Water channel proteins, or aquaporins (AQPs) have been found in large amounts in tumour samples and have a role in the progression of cancer. This study looked at the messenger RNA (mRNA) expression for AQP9 and how this related to survival for patients with renal cell carcinoma (RCC).
The data for this study came from two groups of clear cell RCC patients; the Cancer Genome Atlas (TCGA) database (533 patients) and Fudan University Shanghai Cancer Center (380 patients), which had available RNA-sequencing data. Most of the patients from the Fudan University group had non-metastatic clear cell RCC.
An increase in the expression of AQP9 mRNA was significantly associated with aggressive progression of RCC and correlated with shorter progression-free survival and overall survival in both groups of patients. This study has identified a potentially new oncogene in RCC that could be a promising prognostic biomarker for clear cell RCC and a novel biomarker for response to immunotherapy. Further work is needed to validate AQP9 as a ccRCC biomarker.