BIRC5 and metastatic neoplasm: BIRC5 (Survivin) Inhibitor of apoptosis; cell division regulator. Upregulated in metastatic tumors to allow anoikis resistance and survival in circulation. Supports the survival of proliferating endothelium in tumor vessels. Protects CAFs/myofibroblasts from apoptosis, sustaining pro-metastatic stroma. Ensures MSC survival in harsh metastatic niches.