In addition, a subgroup analysis was conducted using several clinicopathological factors, including age, tumor stage, estrogen receptors, progesterone receptors, human epidermal growth factor receptors 2, and metastasis status, indicating that the nine-TF model displayed good performance for predicting BC prognosis in the majority of the sub-groups (Supplementary Figures S5–S10). Here, PGR is linked to neoplasm.