APOD and breast cancer: Based on the validation of larger external sample data, our results showed that APOD, CXCL14, IL33, and LIFR displayed good prognostic significance (Figure 6), Further, we performed prognostic analysis of breast cancer subtypes, and the results indicated that APOD shows good prognostic value in luminal A breast cancer, IL33 is related to prognosis of Luminal A, Luminal B, HER-2 positive breastV cancer and Triple negative breast cancer (TNBC).