BAX and pachyonychia congenita: It has been found that in vitro treatment of human PC cells with proanthocyanidins from grape seeds resulted in a significant reduction in the cell viability, as well as a significant increase of G2/M phase arrest, induction of apoptosis, decrease in the levels of Bcl-2 and Bcl-xl, and increase in the levels of Bax and activated caspase-3.