PCSK9 and psoriasis: A putative link between psoriasis and PCSK9 activity could be found in research conducted by Cao et al. They demonstrated that elevated tumor necrosis factor alpha (TNF-alfa), one of the crucial pathogenetic factors in psoriasis, suppresses PCSK9 transcription in HepG2 (hepatocellular carcinoma cells) cells and in vivo [30].