PIR and nonpapillary renal cell carcinoma: Previous studies had revealed that piR-32051, piR-39849, and piR-43607 were upregulated in ccRCC [19, 20], whereas other piRNAs like piR-823, piR-38756, piR-57125, piR-34536, and piR51810 were downregulated in tumor tissues [16, 21].