PROS1 and breast cancer: The other three targets are S-phase kinase protein 2 (Skp2), a pro-proliferative, oncogenic protein overexpressed in human BC [173], transmembrane protein 70 (TMEM70), encoded by 8q21 region amplified in BC [174], and importin alpha 3 (KPNA4), a p53 stability regulator that can influence its transcription [175].