High‐throughput qPCR analyses of cancer‐related miRNAs in CUL4B knockdown A549 and control cells showed that much more miRNAs were upregulated (≥ twofold) than those that were downregulated in CUL4B knockdown cells (Appendix S1), suggesting that CUL4B may primarily function to repress the biogenesis of miRNAs. Here, CUL4B is linked to cancer.