For example, piR-651, piR-52200, and piR-34971 have been shown to be upregulated in NSCLC, with piR-651 linked to cancer progression (Li et al., 2016), potentially through regulation of cell cycle control proteins such as cyclin D1 and CDK4 (Li et al., 2016). Here, CDK4 is linked to non-small cell lung carcinoma.