KRAS and renal cell carcinoma: In this study we focused on miR-34a over other miRNAs because of the following reasons: (i) Expression of miR-34a is significantly down-regulated or absent in a variety of cancers including hepatocellular and renal cell carcinomas, colon, breast, lung, prostate, ovarian, and pancreatic cancers [16–22]; (ii) The two major oncogenes that are mutated in PDAC are KRAS and TP53 [23]; (iii) TP53 directly transactivates miR-34a expression [24] while mutated KRAS indirectly lowers expression of miR-34a via the transcription factor, ZEB1 [25, 26].