OTUD7B is known to regulate cell fate and cell proliferation via multiple signaling pathways.[12, 13] Inhibition of LSD1 upon genetic approach or by small molecule compound has been shown to abrogate cell survival or induce G1 arrest in a cell type‐dependent manner.[23, 31] We observed that loss of OTUD7B or LSD1 elicited drastic G1 arrest in breast cancer cells upon synchronization. This evidence concerns the gene KDM1A and breast cancer.