Interestingly, the loss of PUF60, EXOSC4, or BOP1 was also closely correlated with the loss of cell viability in the cell lines of multiple cancer types, except for the skin, eye, and biliary tract cell lines (Figure 4C, Supplementary Figure S21), suggesting the involvement of EXOSC4, PUF60, and BOP1 in the viability of breast cancer cells, in addition to other cancer-relevant functions. This evidence concerns the gene BOP1 and breast cancer.