AQP1 and nonpapillary renal cell carcinoma: AQP1 was revealed to be involved in the regulation of angiogenesis, cell migration and cell growth.[29] AQP1 occupied the largest proportion of studies on AQP function in a diverse array of cancer types.[35] Elevated expression levels of AQP1 in urine were detected in renal cell carcinoma patients,[36,37] and urinary concentrations of AQP1 in renal cell carcinoma correlated with tumor size and stage.[38] According to the present study, the mRNA expression of AQP1 was significantly downregulated in ccRCC tissues from 5 datasets.