PIWIL4 and renal cell carcinoma: Another study reported the association of PIWIL1 in the piR-823-mediated pathogenesis of RCC through the deregulation of PIWIL1 and piR-823 in RCC tumor tissue with a positive correlation, as well as a substantial association has been observed between PIWIL1 and PIWIL2 and PIWIL4 expression and RCC survival (Slaby et al. 2016).