PCSK9 and melanoma: Research on the effect of PCSK9 deficiency on melanoma metastases to the liver carried out in mice concludes that the reduced level of PCSK9 elevates the concentration of proapoptotic TNF-α and decreases the level of anti-apoptotic protein bcl-2, which was clinically manifested by the limitation in the number of liver metastases compared to wild-type mice.