PRRT2 and cancer: Nevertheless, animal studies have shown that bryostatin 1, as a natural macrocyclic lactone with a strong modulator effect on protein kinase C (PKC) isoforms, is active even at subnanomolar concentrations, and the fact that it penetrates the blood–brain barrier gives grounds for considering bryostatin 1 as a potential therapeutic agent not only against cancer but also neurodegenerative diseases.