Conversely, CRISPR/Cas9‐mediated knockdown of USP10 resulted in a reduction in B7‐H4 protein expression but not mRNA level across both MDA‐MB‐468 cells (Figure 2G–J) and SKBR3 breast cancer cells (Figure S2C, Supporting Information), further confirming the regulatory role of USP10 in counteracting B7‐H4 ubiquitylation resulting in B7‐H4 stabilization. This evidence concerns the gene VTCN1 and breast cancer.