An exploratory proof of concept clinical trial on Kaposi’s sarcoma was carried out with the help of our in vitro and in vivo primaquine anti-tumor efficacy and safety findings in PEL cells and mouse models, as well as the fact that primaquine has been used all over the world since the 1950s with remarkable tolerance among glucose 6-phosphate dehydrogenase (G6PD)-normal patients [84]. Here, G6PD is linked to Kaposi's sarcoma.