We assessed transcriptional changes in E2F1, CDK1 and CCND1 whose expression levels correlate with increased cell proliferation and are, in general, elevated in various cancers including breast cancer cells.32, 33, 34, 35 As shown in Figure 6K, the mRNA expression levels of E2F1, CDK1 and CCND1 were reduced, but conversely, the mRNA levels of the tumour suppressor FOXO3 36, 37 were increased in the PIP5Kα knockout SKBR3 cells compared to those in non‐targeting control cells. Here, CDK1 is linked to breast cancer.