Figure 4. Unsupervised hierarchical cluster analysis for the classification of metastatic cancer types (A) and the differences in survival among these three categories in the construction cohort (B) and validation cohort (C). All 61 metastatic cancer types were sub-grouped into three categories, namely, categories (A–C) and the Kaplan-Meier analysis suggested that there were significant differences in prognoses among these categories. Additionally, the survival differences among these categories were validated in the validation cohort.