PAICS and lung cancer: Phosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS), an enzyme that catalyzes de novo purine biosynthesis, has recently been found to have roles in several solid cancers, including lung cancer [11], prostate cancer [12,13], bladder cancer [14], and pancreatic cancer [15].