Although more studies are needed to test this hypothesis, the connection between cancer cell metabolic reprogramming and ALA-PpIX accumulation is supported by another recent study where human glioma cells with mutated TCA cycle enzyme isocitrate dehydrogenase 1 (IDH1) exhibited enhanced ALA-PpIX as compared to cells with wide type IDH1 [46]. Here, IDH1 is linked to central nervous system cancer.