PAICS and neoplasm: We generated two independent stable knockdowns of PPAT and PAICS in A549 cells (Fig. 5A and 5B, inset) and used them in a chicken chorioallantoic membrane (CAM) assay that has been successfully used as an in vivo model to faithfully recapitulate several features of oncogenesis including tumor growth, local invasion and metastasis [49–51].