In order to validate our CRISPR/Cas9 system, we created EGLN2 LOF in HEK293 cells, and as expected, we observed down‐regulation of cyclin D1 on mRNA level (data not shown), suggesting that transcriptional regulation of cyclin D1 in MCL cell lines is not controlled by PHD1. This evidence concerns the gene CCND1 and mantle cell lymphoma.