High expression of COPS5, HDAC2, and NONO was associated with poor OS and disease-free survival in patients with breast cancer (Figures 6C–E) (http://gepia.cancer-pku.cn/ and https://kmplot.com/analysis/), and the associated protein expression was also high in breast cancer (Figure 6F) (https://www.proteinatlas.org/). The gene discussed is HDAC2; the disease is breast cancer.