Efficacy of AOAA was often found to be cell-dependent with primary cells like human skin fibroblasts being very sensitive with 3 μM AOAA shutting down CBS-derived H2S biogenesis [12], while most transformed cells like colon cancer cells required much higher concentrations of 0.1–2 mM AOAA to achieve similar level of inhibition [9, 15, 45]. Here, CBS is linked to malignant colon neoplasm.